In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a combination of computer hardware and computer software. Some explanations of networking found in books and tutorials are highly technical, designed for students and professionals, while others are geared more to home and business uses of computer networks.
Types of Computer Networks
Networks can be categorized in several different ways. One method defines the type of a network according to the geographic area it spans. Alternatively, networks can also be classified based on topology or on the types of protocols they support.
Types of Network Equipment
The building blocks of a home computer network include adapters, routers and/or access points. Wired (and hybrid wired/wireless) networking also involves cables of varying types. Finally, large-scale enterprise networks in particular often employ other advanced equipment for specialized communication purposes.
Ethernet
Ethernet is a physical and data link layer technology for local area networks. Homes, schools and offices around the world all commonly use Ethernet standard cables and adapters to network personal computers.
Wireless Local Area Networks
Wi-Fi is the most popular wireless communication protocol for local area networks. Private home and business networks, and public hotspots, use Wi-Fi to networks computers and other wireless devices to each other and the Internet. Bluetooth is another wireless protocol commonly used in cellular phones and computer peripherals for short range network communication.
Internet Service
The technologies used to connect to the Internet are different than those used for connecting devices on local area network. DSL, cable modem and fiber provide fixed broadband Internet service, while WiMax and LTE additionally support mobile connectivity. In geographic areas where these high-speed options are unavailable, subscribers are forced to use older cellular services, satellite or even dial-up Internet instead.
Friday, December 11, 2009
Network Routing, Switching and Bridging
Most computer networks direct messages from source to destination devices using any of three techniques called routing, switching and bridging. Routers use certain network address information contained inside messages to send them ahead to their destination (sometimes indirectly via one or more additional routers). Switches use much of the same technology as routers but typically support local area networks only. Bridging allows messages to flow between two different types of physical networks.
What is (Wireless / Computer) Networking?
In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.
Area Networks
Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.
Area Networks
Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.
Network Design
Computer networks also differ in their design. The two types of high-level network design are called client-server and peer-to-peer. Client-server networks feature centralized server computers that store email, Web pages, files and or applications. On a peer-to-peer network, conversely, all computers tend to support the same functions. Client-server networks are much more common in business and peer-to-peer networks much more common in homes.
A network topology represents its layout or structure from the point of view of data flow. In so-called bus networks, for example, all of the computers share and communicate across one common conduit, whereas in a star network, all data flows through one centralized device. Common types of network topologies include bus, star, ring and mesh.
A network topology represents its layout or structure from the point of view of data flow. In so-called bus networks, for example, all of the computers share and communicate across one common conduit, whereas in a star network, all data flows through one centralized device. Common types of network topologies include bus, star, ring and mesh.
Network Protocols
In networking, the communication language used by computer devices is called the protocol. Yet another way to classify computer networks is by the set of protocols they support. Networks often implement multiple protocols to support specific applications. Popular protocols include TCP/IP, the most common protocol found on the Internet and in home networks.
Wired vs Wireless Networking
Many of the same network protocols, like TCP/IP, work in both wired and wireless networks. Networks with Ethernet cables predominated in businesses, schools, and homes for several decades. Recently, however, wireless networking alternatives have emerged as the premier technology for building new computer networks.
Tuesday, November 10, 2009
Introduction to Wireless Network Security
Birth of Wireless Home Networking
It wasn’t too long ago that computers were a luxury rather than a necessity. Only the lucky and the wealthy had even one in their home and a network was something reserved for large corporations.
Fast forward a decade or so and everyone has to have their own computer. There is one for the parents (sometimes two if the parents can’t share nice) and one or more for the kids to use for homework and games. Home users have gone from no Internet access to 9600 kbps dial-up Internet access beyond 56 kbps dial-up access and are moving on to broadband connections to rival or match the T1 connections they relish at work.
As the Internet and the World Wide Web have exploded into our culture and are replacing other media forms for people to find news, weather, sports, recipes, yellow pages and a million other things, the new struggle is not only for time on the computer at home, but for time on the Internet connection.
The hardware and software vendors have come forth with a variety of solutions allowing home users to share one Internet connection among two or more computers. They all have one thing in common though- the computers must somehow be networked.
To connect your computers together has traditionally involved having some physical medium running between them. It could be phone wire, coaxial cable or the ubiquitous CAT5 cable. Recently hardware has been introduced that even lets home users network computers through the electrical wiring. But, one of the easiest and least messy ways to network computers throughout your home is to use wireless technology.
It is a fairly simple setup. The Internet connection comes in from your provider and is connected to a wireless access point or router which broadcasts the signal. You connect wireless antenna network cards to your computers to receive that signal and talk back to the wireless access point and you are in business.
The problem with having the signal broadcast though is that it is difficult to contain where that signal may travel. If it can get from upstairs to your office in the basement then it can also go that same 100 feet to your neighbors living room. Or, a hacker searching for insecure wireless connections can get into your systems from a car parked on the street.
That doesn’t mean you shouldn’t use wireless networking. You just have to be smart about it and take some basic precautions to make it more difficult for curiosity seekers to get into your personal information. The next section contains some simple steps you can take to secure your wireless network.
Security in 6 Easy Steps
1). Change the System ID:
Devices come with a default system ID called the SSID (Service Set Identifier) or ESSID (Extended Service Set Identifier). It is easy for a hacker to find out what the default identifier is for each manufacturer of wireless equipment so you need to change this to something else. Use something unique- not your name or something easily guessed.
2).Disable Identifier Broadcasting:
Announcing that you have a wireless connection to the world is an invitation for hackers. You already know you have one so you don’t need to broadcast it. Check the manual for your hardware and figure out how to disable broadcasting.
3).Enable Encryption:
WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) encrypt your data so that only the intended recipient is supposed to be able to read it. WEP has many holes and is easily cracked. 128-bit keys impact performance slightly without a significant increase in security so 40-bit (or 64-bit on some equipment) encryption is just as well. As with all security measures there are ways around it, but by using encryption you will keep the casual hackers out of your systems. If possible, you should use WPA encryption (most older equipment can be upgraded to be WPA compatible). WPA fixes the security flaws in WEP but it is still subject to DOS (denial-of-service) attacks.
4).Restrict Unnecessary Traffic:
Many wired and wireless routers have built-in firewalls. They are not the most technically advanced firewalls, but they help create one more line of defense. Read the manual for your hardware and learn how to configure your router to only allow incoming or outgoing traffic that you have approved.
5).Change the Default Administrator Password:
This is just good practice for ALL hardware and software. The default passwords are easily obtained and because so many people don’t bother to take the simple step of changing them they are usually what hackers try first. Make sure you change the default password on your wireless router / access point to something that is not easily guessed like your last name.
6).Patch and Protect Your PC’s:
As a last line of defense you should have personal firewall software such as Zone Alarm Pro and anti-virus software installed on your computer. As important as installing the anti-virus software, you must keep it up to date. New viruses are discovered daily and anti-virus software vendors generally release updates at least once a week. You also must keep up to date with patches for known security vulnerabilities. For Microsoft operating systems you can use Windows Update to try and help keep you current with patches.
It wasn’t too long ago that computers were a luxury rather than a necessity. Only the lucky and the wealthy had even one in their home and a network was something reserved for large corporations.
Fast forward a decade or so and everyone has to have their own computer. There is one for the parents (sometimes two if the parents can’t share nice) and one or more for the kids to use for homework and games. Home users have gone from no Internet access to 9600 kbps dial-up Internet access beyond 56 kbps dial-up access and are moving on to broadband connections to rival or match the T1 connections they relish at work.
As the Internet and the World Wide Web have exploded into our culture and are replacing other media forms for people to find news, weather, sports, recipes, yellow pages and a million other things, the new struggle is not only for time on the computer at home, but for time on the Internet connection.
The hardware and software vendors have come forth with a variety of solutions allowing home users to share one Internet connection among two or more computers. They all have one thing in common though- the computers must somehow be networked.
To connect your computers together has traditionally involved having some physical medium running between them. It could be phone wire, coaxial cable or the ubiquitous CAT5 cable. Recently hardware has been introduced that even lets home users network computers through the electrical wiring. But, one of the easiest and least messy ways to network computers throughout your home is to use wireless technology.
It is a fairly simple setup. The Internet connection comes in from your provider and is connected to a wireless access point or router which broadcasts the signal. You connect wireless antenna network cards to your computers to receive that signal and talk back to the wireless access point and you are in business.
The problem with having the signal broadcast though is that it is difficult to contain where that signal may travel. If it can get from upstairs to your office in the basement then it can also go that same 100 feet to your neighbors living room. Or, a hacker searching for insecure wireless connections can get into your systems from a car parked on the street.
That doesn’t mean you shouldn’t use wireless networking. You just have to be smart about it and take some basic precautions to make it more difficult for curiosity seekers to get into your personal information. The next section contains some simple steps you can take to secure your wireless network.
Security in 6 Easy Steps
1). Change the System ID:
Devices come with a default system ID called the SSID (Service Set Identifier) or ESSID (Extended Service Set Identifier). It is easy for a hacker to find out what the default identifier is for each manufacturer of wireless equipment so you need to change this to something else. Use something unique- not your name or something easily guessed.
2).Disable Identifier Broadcasting:
Announcing that you have a wireless connection to the world is an invitation for hackers. You already know you have one so you don’t need to broadcast it. Check the manual for your hardware and figure out how to disable broadcasting.
3).Enable Encryption:
WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) encrypt your data so that only the intended recipient is supposed to be able to read it. WEP has many holes and is easily cracked. 128-bit keys impact performance slightly without a significant increase in security so 40-bit (or 64-bit on some equipment) encryption is just as well. As with all security measures there are ways around it, but by using encryption you will keep the casual hackers out of your systems. If possible, you should use WPA encryption (most older equipment can be upgraded to be WPA compatible). WPA fixes the security flaws in WEP but it is still subject to DOS (denial-of-service) attacks.
4).Restrict Unnecessary Traffic:
Many wired and wireless routers have built-in firewalls. They are not the most technically advanced firewalls, but they help create one more line of defense. Read the manual for your hardware and learn how to configure your router to only allow incoming or outgoing traffic that you have approved.
5).Change the Default Administrator Password:
This is just good practice for ALL hardware and software. The default passwords are easily obtained and because so many people don’t bother to take the simple step of changing them they are usually what hackers try first. Make sure you change the default password on your wireless router / access point to something that is not easily guessed like your last name.
6).Patch and Protect Your PC’s:
As a last line of defense you should have personal firewall software such as Zone Alarm Pro and anti-virus software installed on your computer. As important as installing the anti-virus software, you must keep it up to date. New viruses are discovered daily and anti-virus software vendors generally release updates at least once a week. You also must keep up to date with patches for known security vulnerabilities. For Microsoft operating systems you can use Windows Update to try and help keep you current with patches.
What Are the Benefits of Networking?
The benefits of networking (either wired or wireless) in homes are:
file sharing -
Network file sharing between computers gives you more flexibity than using floppy drives or Zip drives. Not only can you share photos, music files, and documents, you can also use a home network to save copies of all of your important data on a different computer. Backups are one of the most critical yet overlooked tasks in home networking.
printer / peripheral sharing -
Once a home network is in place, it's easy to then set up all of the computers to share a single printer. No longer will you need to bounce from one system or another just to print out an email message. Other computer peripherals can be shared similarly such as network scanners, Web cams, and CD burners.
Internet connection sharing -
Using a home network, multiple family members can access the Internet simultaneously without having to pay an ISP for multiple accounts. You will notice the Internet connection slows down when several people share it, but broadband Internet can handle the extra load with little trouble. Sharing dial-up Internet connections works, too. Painfully slow sometimes, you will still appreciate having shared dial-up on those occasions you really need it.
multi-player games -
Many popular home computer games support LAN mode where friends and family can play together, if they have their computers networked.
Internet telephone service - So-called Voice over IP (VoIP) services allow you to make and receive phone calls through your home network across the Internet, saving you money.
home entertainment - Newer home entertainment products such as digital video recorders (DVRs) and video game consoles now support either wired or wireless home networking. Having these products integrated into your network enables online Internet gaming, video sharing and other advanced features.
Although you can realize these same benefits with a wired home network, you should carefully consider building a wireless home network instead, for the following reasons:
1. Computer mobility.
Notebook computers and other portable devices are much affordable than they were a few years ago. With a mobile computer and wireless home network, you aren't chained to a network cord and can work on the couch, on your porch, or wherever in the house is most convenient at the moment.
2. No unsightly wires.
Businesses can afford to lay cable under their floors or inside walls. But most of us don't have the time or inclination to fuss with this in our home. Unless you own one of the few newer homes pre-wired with network cable, you'll save substantial time and energy avoiding the cabling mess and going wireless.
3. Wireless is the future.
Wireless technology is clearly the future of networking. In building a wireless home network, you'll learn about the technology and be able to teach your friends and relatives. You'll also be better prepared for future advances in network technology coming in the future.
file sharing -
Network file sharing between computers gives you more flexibity than using floppy drives or Zip drives. Not only can you share photos, music files, and documents, you can also use a home network to save copies of all of your important data on a different computer. Backups are one of the most critical yet overlooked tasks in home networking.
printer / peripheral sharing -
Once a home network is in place, it's easy to then set up all of the computers to share a single printer. No longer will you need to bounce from one system or another just to print out an email message. Other computer peripherals can be shared similarly such as network scanners, Web cams, and CD burners.
Internet connection sharing -
Using a home network, multiple family members can access the Internet simultaneously without having to pay an ISP for multiple accounts. You will notice the Internet connection slows down when several people share it, but broadband Internet can handle the extra load with little trouble. Sharing dial-up Internet connections works, too. Painfully slow sometimes, you will still appreciate having shared dial-up on those occasions you really need it.
multi-player games -
Many popular home computer games support LAN mode where friends and family can play together, if they have their computers networked.
Internet telephone service - So-called Voice over IP (VoIP) services allow you to make and receive phone calls through your home network across the Internet, saving you money.
home entertainment - Newer home entertainment products such as digital video recorders (DVRs) and video game consoles now support either wired or wireless home networking. Having these products integrated into your network enables online Internet gaming, video sharing and other advanced features.
Although you can realize these same benefits with a wired home network, you should carefully consider building a wireless home network instead, for the following reasons:
1. Computer mobility.
Notebook computers and other portable devices are much affordable than they were a few years ago. With a mobile computer and wireless home network, you aren't chained to a network cord and can work on the couch, on your porch, or wherever in the house is most convenient at the moment.
2. No unsightly wires.
Businesses can afford to lay cable under their floors or inside walls. But most of us don't have the time or inclination to fuss with this in our home. Unless you own one of the few newer homes pre-wired with network cable, you'll save substantial time and energy avoiding the cabling mess and going wireless.
3. Wireless is the future.
Wireless technology is clearly the future of networking. In building a wireless home network, you'll learn about the technology and be able to teach your friends and relatives. You'll also be better prepared for future advances in network technology coming in the future.
Wired vs Wireless Networking
The home networker can choose from either wireless or wired designs. Wireless networks provide more mobility to a person in and around their home, and they make especially good sense for laptop networking.
Networks with wires or cables, on the other hand, usually cost less than wireless, may perform faster and more reliably, and make good sense for desktop networking.
Choosing between wired and wireless options can be difficult, but making an informed decision here can save money and increase one's overall satisfaction with their home network.
Networks with wires or cables, on the other hand, usually cost less than wireless, may perform faster and more reliably, and make good sense for desktop networking.
Choosing between wired and wireless options can be difficult, but making an informed decision here can save money and increase one's overall satisfaction with their home network.
Home Networking Tutorial
Planning a New Home Network
Before purchasing and installing equipment, determine your needs. The location of your computer(s), printer(s) and other devices you want to connect can affect your network design. Some systems may already contain built-in networking capability while others may not.
Those devices that need network capability added, probably support only certain kinds of network gear. Take care to buy compatible gear.
If you desire shared Internet access, be sure to factor this into your design. Other important factors in network design include reach and speed.
Finally, consider both present and future needs in your plan. How many computers will your network have in the next year or two? A network with just two computers can involve a very different design than a network with five, for example.
Use our interactive network advisor tool to walk you through the factors to consider when designing your home network.
Before purchasing and installing equipment, determine your needs. The location of your computer(s), printer(s) and other devices you want to connect can affect your network design. Some systems may already contain built-in networking capability while others may not.
Those devices that need network capability added, probably support only certain kinds of network gear. Take care to buy compatible gear.
If you desire shared Internet access, be sure to factor this into your design. Other important factors in network design include reach and speed.
Finally, consider both present and future needs in your plan. How many computers will your network have in the next year or two? A network with just two computers can involve a very different design than a network with five, for example.
Use our interactive network advisor tool to walk you through the factors to consider when designing your home network.
Our First Virtual Event: Next Generation Networking
Posted by Mike Fratto on November 9, 2009
On November 12th, we will be hosting our first virtual event covering next generation networking. You can register here. We have a great line-up of speakers, including a keynote by Rob Roy, CEO of Switch Communications, which runs the SuperNAP in Las Vegas. The rest of the day includes presentations on key networking topics delivered by IT practitioners and experts as well as sponsors. I've seen the presentations, and like what I see.
Naturally, I am biased. Still, if you are interested in the topics Network Computing is delivering, like converged networking, WAN optimization integrating virtual and physical networks, and in hearing the insights offered by people who have had their hands on the technology or are considering it for their own IT shops, this is something you don't want to miss.Peppered throughout the day are presentations by the show sponsors that not only shed light on the direction vendors are taking, but which also provide insights into features and uses of their products that aren't necessarily apparent.
It's also a good time to get your questions answered, or at least to collect some new ones for the next vendor meeting. The event takes place in a virtual environment where you can visit vendor booths, interact with them and grab white papers and other literature. There is also a lounge where you can talk with other attendees and staff. It's a good way to meet and talk with peers. So come on by! We'd love to hear your comments on what you liked, or didn't, and any other thoughts you might like to share about this virtual event.
On November 12th, we will be hosting our first virtual event covering next generation networking. You can register here. We have a great line-up of speakers, including a keynote by Rob Roy, CEO of Switch Communications, which runs the SuperNAP in Las Vegas. The rest of the day includes presentations on key networking topics delivered by IT practitioners and experts as well as sponsors. I've seen the presentations, and like what I see.
Naturally, I am biased. Still, if you are interested in the topics Network Computing is delivering, like converged networking, WAN optimization integrating virtual and physical networks, and in hearing the insights offered by people who have had their hands on the technology or are considering it for their own IT shops, this is something you don't want to miss.Peppered throughout the day are presentations by the show sponsors that not only shed light on the direction vendors are taking, but which also provide insights into features and uses of their products that aren't necessarily apparent.
It's also a good time to get your questions answered, or at least to collect some new ones for the next vendor meeting. The event takes place in a virtual environment where you can visit vendor booths, interact with them and grab white papers and other literature. There is also a lounge where you can talk with other attendees and staff. It's a good way to meet and talk with peers. So come on by! We'd love to hear your comments on what you liked, or didn't, and any other thoughts you might like to share about this virtual event.
Home Computer Networks 101
Guide to Wired and Wireless Home Networking
This page serves as your starting point for learning about the world of home computer networking, step by step. We will teach you all of the basics of home network planning, installation, and troubleshooting assuming no prior knowledge of network technology.
Background
Computer networks have existed for more than thirty years, but only relatively recently have they become popular in homes. In 1999, only a few hundred thousand households in the United States possessed a home network, although many more "expressed interest" in having one.
Today, many millions of households in the U.S. and worldwide have adopted home computer networking. Millions more have yet to build their first home network. Even those who've previously taken the plunge are now beginning to revamp their networks for wireless - the current wave of useful technology for home networking.
Depending on your present goals and past experience, varying types of information may be relevant to your situation. Use the outline below as a comprehensive guide to your personal research.
Do I Really Need a Home Computer Network?
Some of you likely share files between your computers using floppy disks or USB keys. A home network allows you to share these files much faster and more conveniently by utilizing the available connections between computers.
Home networks allow sharing of other things, too, like a printer and an Internet connection. Finally, home networks create the possibility to use new applications like multi-player online games.
This page serves as your starting point for learning about the world of home computer networking, step by step. We will teach you all of the basics of home network planning, installation, and troubleshooting assuming no prior knowledge of network technology.
Background
Computer networks have existed for more than thirty years, but only relatively recently have they become popular in homes. In 1999, only a few hundred thousand households in the United States possessed a home network, although many more "expressed interest" in having one.
Today, many millions of households in the U.S. and worldwide have adopted home computer networking. Millions more have yet to build their first home network. Even those who've previously taken the plunge are now beginning to revamp their networks for wireless - the current wave of useful technology for home networking.
Depending on your present goals and past experience, varying types of information may be relevant to your situation. Use the outline below as a comprehensive guide to your personal research.
Do I Really Need a Home Computer Network?
Some of you likely share files between your computers using floppy disks or USB keys. A home network allows you to share these files much faster and more conveniently by utilizing the available connections between computers.
Home networks allow sharing of other things, too, like a printer and an Internet connection. Finally, home networks create the possibility to use new applications like multi-player online games.
What is (Wireless / Computer) Networking?
In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.
Area Networks
Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.
Network Design
Computer networks also differ in their design. The two types of high-level network design are called client-server and peer-to-peer. Client-server networks feature centralized server computers that store email, Web pages, files and or applications. On a peer-to-peer network, conversely, all computers tend to support the same functions. Client-server networks are much more common in business and peer-to-peer networks much more common in homes.
A network topology represents its layout or structure from the point of view of data flow. In so-called bus networks, for example, all of the computers share and communicate across one common conduit, whereas in a star network, all data flows through one centralized device. Common types of network topologies include bus, star, ring and mesh.
Network Protocols
In networking, the communication language used by computer devices is called the protocol. Yet another way to classify computer networks is by the set of protocols they support. Networks often implement multiple protocols to support specific applications. Popular protocols include TCP/IP, the most common protocol found on the Internet and in home networks.
Wired vs Wireless Networking
Many of the same network protocols, like TCP/IP, work in both wired and wireless networks. Networks with Ethernet cables predominated in businesses, schools, and homes for several decades. Recently, however, wireless networking alternatives have emerged as the premier technology for building new computer networks.
Area Networks
Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.
Network Design
Computer networks also differ in their design. The two types of high-level network design are called client-server and peer-to-peer. Client-server networks feature centralized server computers that store email, Web pages, files and or applications. On a peer-to-peer network, conversely, all computers tend to support the same functions. Client-server networks are much more common in business and peer-to-peer networks much more common in homes.
A network topology represents its layout or structure from the point of view of data flow. In so-called bus networks, for example, all of the computers share and communicate across one common conduit, whereas in a star network, all data flows through one centralized device. Common types of network topologies include bus, star, ring and mesh.
Network Protocols
In networking, the communication language used by computer devices is called the protocol. Yet another way to classify computer networks is by the set of protocols they support. Networks often implement multiple protocols to support specific applications. Popular protocols include TCP/IP, the most common protocol found on the Internet and in home networks.
Wired vs Wireless Networking
Many of the same network protocols, like TCP/IP, work in both wired and wireless networks. Networks with Ethernet cables predominated in businesses, schools, and homes for several decades. Recently, however, wireless networking alternatives have emerged as the premier technology for building new computer networks.
Monday, September 14, 2009
Computer Networking ?
To share data and network resources among the computers in a network is known as networking. Computer networking is a core part of the whole information technology field because without it computers can never communication with each other locally and remotely. Just image that if you work in a bank or in a corporate office and all the computers in your office are without networking. How difficult it would be for you and for the other employees of your office to communications, shares data such as word documents, financial reports, client’s feedback, graphical reports and other important work with the other employees.
Put the same scenario if your office has different branches in the same country and different countries. Data communication has become the vital part of the whole computing industry. There are different standards, protocols, devices and applications that form computer network architecture. With the passage of time there are improved standards, communication devices and network applications that make the data communication processor easier. Following is the basic review of the important things that are involved in the data communication system.
TCP/IP
Protocols are the set of rules, agree upon ways and communication standards that computer and devices use to communication with each other. TCP/IP stands for transmission control protocol/Internet protocol. TCP/IP is the standard protocol for network communication in LAN or WAN. All the devices and applications have to follow to same protocols to make network communication system.
Put the same scenario if your office has different branches in the same country and different countries. Data communication has become the vital part of the whole computing industry. There are different standards, protocols, devices and applications that form computer network architecture. With the passage of time there are improved standards, communication devices and network applications that make the data communication processor easier. Following is the basic review of the important things that are involved in the data communication system.
TCP/IP
Protocols are the set of rules, agree upon ways and communication standards that computer and devices use to communication with each other. TCP/IP stands for transmission control protocol/Internet protocol. TCP/IP is the standard protocol for network communication in LAN or WAN. All the devices and applications have to follow to same protocols to make network communication system.
Communication Devices
There are certain devices that are used in LAN/MAN/WAN and wireless networking. The most important devices are router, switch, hub, modem, NIC adapter, access points, broadband router and communication cables. Hub/Switch is a centralized device in a LAN and all the computers connect with the Hub/Switch. In case of failure of Hub/Switch the whole communication stops. Router routes the traffic to the destination based on the IP address of the source and destination computer. With the help of the routing table, the router chooses the best short possible path for data to be sent to its destination. Wireless routers and access points are used in the wireless networking.
There are certain devices that are used in LAN/MAN/WAN and wireless networking. The most important devices are router, switch, hub, modem, NIC adapter, access points, broadband router and communication cables. Hub/Switch is a centralized device in a LAN and all the computers connect with the Hub/Switch. In case of failure of Hub/Switch the whole communication stops. Router routes the traffic to the destination based on the IP address of the source and destination computer. With the help of the routing table, the router chooses the best short possible path for data to be sent to its destination. Wireless routers and access points are used in the wireless networking.
Types of Networking
There are three main types of the computer networking such as LAN, MAN and WAN. A LAN covers a room or a building. A MAN covers a network in a city and a WAN covers wide areas such as in a city, country or a network between two or more countries. A LAN can be wired or wireless, MAN can be wired or Wireless and WAN can be through wireless communication technologies such as ISDN lines, frame relay and ATM.
Wireless Networking
Wireless networks are replacing the wired networks rapidly. The administrative control becomes less due to the removal of the bundle of cables in wireless network. The key components are wireless router, access points and PCMCIA LAN cards.
OSI Layers Model
To understand the communication process make the data communication process standardized, the ISO developed the OSI (open system interconnectivity, which defines the seven layers of the OSI model. These seven layers include Application, Presentation, Session, Transport, Network, Data Link and Physical layer. The detail on the OSI seven layers is covered in the separate topic of this website.
To understand the communication process make the data communication process standardized, the ISO developed the OSI (open system interconnectivity, which defines the seven layers of the OSI model. These seven layers include Application, Presentation, Session, Transport, Network, Data Link and Physical layer. The detail on the OSI seven layers is covered in the separate topic of this website.
DHCP
DHCP stands for the dynamic host configuration protocol. As we know that a unique IP address is a must for communication in LAN, WAN or internet. Assume you are given the task to assign IP addresses to the 10,000 computers in a network. How would you assign? DHCP answers this questions and it assigns the unique IP addresses to all the computers from a given range. There is an administrative control and you can block, assign, lease, renew, specify duration for the IP address and you also do the many other administrative tasks on the DHCP.
DNS
DNS stands for domain name system. DNS translates (converts) the host name into the IP address and IP address into the host name. One thing is clear that the communication in a LAN private WAN or internet is based on the IP addresses. On internet every IP address is associated with the domain name let’s say assume that the IP address 120.1.1.1. is assigned to www.yahoo.com, 12.1.2.3 is assigned to www.google.com and 35.22.32.5 is assigned to www.msn.com and so on. Just imagine that how many IP addresses you can remember 1, 2, 5, 10, 50, 100 or 1000. IP addresses are actually difficult to remember and domain names are easy so every IP address on the internet is associated with a domain name.
Wi-Fi
Wireless fidelity is a base band wireless networking technology that provides high speed internet connectivity to the offices and home users.
Wi-Max
Wi-Max is an advance broadband wireless network technology that provides very high speed up to 70 Mbps. Wi-Max is designed for the corporate office, roaming and home users.
Internet is an example of Network
Internet is the largest network in the work. Millions of computers from all over the world are internetworked with each other and are the part of the internet. The resources hosted on one computer in one part of the world such as web pages, songs files, graphics, video files, documents and images are accessible to the users in another part of the world.
OSI 7 Layers Reference Model
OSI 7 Layers Reference Model
Here you will learn OSI Model Layer Introduction, overview of the 7 OSI reference model, applicaion, session, transport, network and physical layers. If you want to remember the sequence of the OSI layers model name then the following two sentences can help you a lot for this purpose.“All People Seems To Need Data Processing”. Open Systems Interconnection (OSI) model is developed by ISO (International organization for standardization) in 1984.
OSI reference model is a logical framework for standards for the network communication.
OSI reference model is now considered as a primary standard for internetworking and inter computing. Today many network communication protocols are based on the standards of OSI model. In the OSI model the network/data communication is defined into seven layers.
These 7 layers further divide the tasks of moving the data across the network into subtask and hence complete one communication cycle between two computers or two network devices. Each layer is assigned a task and the task is completed independently. The OSI layers have the clear and independent characteristics and tasks.
The 7 layers of the OSI models can be divided into upper and lower layers. I have defined the characteristics, tasks and features of each layer separately.
Layer 7: Application Layer
The application layer defines the interfaces for communication and data transfer. This layer also provides and support services such as job transfer, handles network access, e-mail, supports user applications and error recovery.
Protocols: FTP, DNS, SNMP, SMTP, FINGER, TELNET, TFTP, BOOTP and SMB protocol are operated on the application layer.
Network Devices: Gateway network device is operated on the application layer.
Layer 6:Presentation Layer
The presentation layer presents the data into a uniform format and masks the difference of data format between two dissimilar systems. It also translates the data from application to the network format. Presentation layer is also responsible for the protocol conversion, encryption, decryption and data compression. Presentation layer is a best layer for cryptography. Network Devices: Gateway Redirector is operates on the presentation layer.
Layer 5: Session Layer
Session layer establish and manages the session between the two users at different ends in a network. Session layer also manages who can transfer the data in a certain amount of time and for how long. The examples of session layers and the interactive logins and file transfer sessions. Session layer reconnect the session if it disconnects. It also reports and logs and upper layer errors.Protocols: The protocols that work on the session layer are NetBIOS, Mail Slots, Names Pipes, RPC Network Devices: Gateway
Layer 4: Transport Layer
Transport layer manages end to end message delivery in a network and also provides the error checking and hence guarantees that no duplication or errors are occurring in the data transfers across the network. Transport layer also provides the acknowledgement of the successful data transmission and retransmits the data if no error free data was transferred. It also provides and error handling and connectionless oriented data deliver in the network. Protocols: These protocols work on the transport layer TCP, SPX, NETBIOS, ATP and NWLINK.
Network Devices: The Brouter, Gateway and Cable tester work on the transport layer.
Layer 3: Network Layer
The network layer determines that how data transmits between the network devices. It also translates the logical address into the physical address e.g computer name into MAC address. It is also responsible for defining the route, managing the network problems and addressing. Router works on the network layer and if a sending device does not break the data into the similar packets as the receiving device then network layer split the data into the smaller units and at the receiving end the network layer reassemble the data.
Network layer routes the packets according to the unique network addresses. Router works as the post office and network layer stamps the letters (data) for the specific destinations. Protocols: These protocols work on the network layer IP, ICMP, ARP, RIP, OSI, IPX and OSPF. Network Devices: Network devices including Router, Brouter, Frame Relay device and ATM switch devices work on the network layer.
Layer 2:Data Link Layer
Defines procedures for operating the communication links
Frames packetsDetects and corrects packets transmit errors
Protocols: Logical Link Control
• error correction and flow control
• manages link control and defines SAPs
802.1 OSI Model
802.2 Logical Link Control
Media Access Control
• communicates with the adapter card
• controls the type of media being used:
802.3 CSMA/CD (Ethernet)
802.4 Token Bus (ARCnet)
802.5 Token Ring
802.12 Demand Priority
Network Devices: Bridge
Switch
ISDN Router
Intelligent Hub
NIC
Advanced Cable Tester
Layer 1: Physical Layer
Physical layer defines and cables, network cards and physical aspects. It defines raw bit stream on the physical media. It also provides the interface between network and network communication devices. It is also responsible for how many volts for 0 and how many for 1. Physical layer also checks the number of bits transmitted per second and two ways or one way transmission. Physical layer also dealing with the optical, mechanical and electrical features.
Protocols: Protocols that work on the physical layer are ISDN, IEEE 802 and IEEE 802.2
Network Devices: Hubs, Repeaters, Oscilloscope and Amplifier works on the network devices.
Here you will learn OSI Model Layer Introduction, overview of the 7 OSI reference model, applicaion, session, transport, network and physical layers. If you want to remember the sequence of the OSI layers model name then the following two sentences can help you a lot for this purpose.“All People Seems To Need Data Processing”. Open Systems Interconnection (OSI) model is developed by ISO (International organization for standardization) in 1984.
OSI reference model is a logical framework for standards for the network communication.
OSI reference model is now considered as a primary standard for internetworking and inter computing. Today many network communication protocols are based on the standards of OSI model. In the OSI model the network/data communication is defined into seven layers.
These 7 layers further divide the tasks of moving the data across the network into subtask and hence complete one communication cycle between two computers or two network devices. Each layer is assigned a task and the task is completed independently. The OSI layers have the clear and independent characteristics and tasks.
The 7 layers of the OSI models can be divided into upper and lower layers. I have defined the characteristics, tasks and features of each layer separately.
Layer 7: Application Layer
The application layer defines the interfaces for communication and data transfer. This layer also provides and support services such as job transfer, handles network access, e-mail, supports user applications and error recovery.
Protocols: FTP, DNS, SNMP, SMTP, FINGER, TELNET, TFTP, BOOTP and SMB protocol are operated on the application layer.
Network Devices: Gateway network device is operated on the application layer.
Layer 6:Presentation Layer
The presentation layer presents the data into a uniform format and masks the difference of data format between two dissimilar systems. It also translates the data from application to the network format. Presentation layer is also responsible for the protocol conversion, encryption, decryption and data compression. Presentation layer is a best layer for cryptography. Network Devices: Gateway Redirector is operates on the presentation layer.
Layer 5: Session Layer
Session layer establish and manages the session between the two users at different ends in a network. Session layer also manages who can transfer the data in a certain amount of time and for how long. The examples of session layers and the interactive logins and file transfer sessions. Session layer reconnect the session if it disconnects. It also reports and logs and upper layer errors.Protocols: The protocols that work on the session layer are NetBIOS, Mail Slots, Names Pipes, RPC Network Devices: Gateway
Layer 4: Transport Layer
Transport layer manages end to end message delivery in a network and also provides the error checking and hence guarantees that no duplication or errors are occurring in the data transfers across the network. Transport layer also provides the acknowledgement of the successful data transmission and retransmits the data if no error free data was transferred. It also provides and error handling and connectionless oriented data deliver in the network. Protocols: These protocols work on the transport layer TCP, SPX, NETBIOS, ATP and NWLINK.
Network Devices: The Brouter, Gateway and Cable tester work on the transport layer.
Layer 3: Network Layer
The network layer determines that how data transmits between the network devices. It also translates the logical address into the physical address e.g computer name into MAC address. It is also responsible for defining the route, managing the network problems and addressing. Router works on the network layer and if a sending device does not break the data into the similar packets as the receiving device then network layer split the data into the smaller units and at the receiving end the network layer reassemble the data.
Network layer routes the packets according to the unique network addresses. Router works as the post office and network layer stamps the letters (data) for the specific destinations. Protocols: These protocols work on the network layer IP, ICMP, ARP, RIP, OSI, IPX and OSPF. Network Devices: Network devices including Router, Brouter, Frame Relay device and ATM switch devices work on the network layer.
Layer 2:Data Link Layer
Defines procedures for operating the communication links
Frames packetsDetects and corrects packets transmit errors
Protocols: Logical Link Control
• error correction and flow control
• manages link control and defines SAPs
802.1 OSI Model
802.2 Logical Link Control
Media Access Control
• communicates with the adapter card
• controls the type of media being used:
802.3 CSMA/CD (Ethernet)
802.4 Token Bus (ARCnet)
802.5 Token Ring
802.12 Demand Priority
Network Devices: Bridge
Switch
ISDN Router
Intelligent Hub
NIC
Advanced Cable Tester
Layer 1: Physical Layer
Physical layer defines and cables, network cards and physical aspects. It defines raw bit stream on the physical media. It also provides the interface between network and network communication devices. It is also responsible for how many volts for 0 and how many for 1. Physical layer also checks the number of bits transmitted per second and two ways or one way transmission. Physical layer also dealing with the optical, mechanical and electrical features.
Protocols: Protocols that work on the physical layer are ISDN, IEEE 802 and IEEE 802.2
Network Devices: Hubs, Repeaters, Oscilloscope and Amplifier works on the network devices.
Basic Network Security Tips
This basic Network Security Guide provides useful security tips and methods to secure your network such as installing a updated antivirus program, email scanning programs, network monitoring tools, internet access policy and other security prevention methods. Network security is a very important aspect of a computer network. Minor security vulnerability can result in a heavy loss of the critical data of your server and other client computers. Keeping the computer as well as network secure, is the big responsibility of the network administrator and the security specialists. There are lot of security measures and prevention methods which I will discuss in this section. Typically a computer network can be attacked by a number of ways such as virus attacks, unauthorized access, cryptography attacks and a number of other security threats.
A network security threat can be prevented if you have an updated antivirus program, regularly scan all the network devices, emails, open ports, server and client computers. It’s the responsibility of the network administrators to check and deploy the missing security patches in all the network computers. They should also remove the unnecessary network shares, users accounts, wireless access points and restrict the access too the network users. There should be proper training of the network users, network administrators and IT managers about the vulnerable things that cause a network to be attacked. A network administration of an organization should be highly skilled person and have much experience in network/system administration as well as dealing with the security issues.
Security Threats
There are a number of security threats that can be the cause of a network security attack. Main security threats are denial of service, distributed denial of service, viruses, Trojan horses, spywares, malwares, unauthorized access to the network resources and data, accidental deletion of the files and the uncontrolled internet access.
Virus Attack
A computer virus is a small program or an executable code that when executed and replicated, perform different unwanted and harmful functions for a computer and a network. Viruses can destroy your hard disks and processors, consume memory at a very large scale and destroy the overall performance of a computer or network. A Trojan is a malicious code that performs harmful actions but it cannot be replicated. Trojan can destroy systems’ critical data. A computer worm is a program that replicates to all network and destroy useful data. The viruses, malware, adware and Trojan horses can be prevented if you have an updated antivirus program with the latest pattern files.
Security policy
Being a network administrator, you should implement a security policy in your network and educate your network users and other employees about the security threats.
Email scanning
Email is a big source of a virus and malicious code. You should have installed an email scanning and monitoring program. You should also have a tight security policy at your proxy server and should block the unnecessary ports and web applications.
Unauthorized Access
Access to the network resources and data should be allowed only to the authorized persons. Every shared folder and resources in your network should have been accessed only by the authorized persons and should also be scanned and monitored regularly.
Accidental deletion of the files
What will you do if you accidentally delete your organization’s critical data? This is a question, which every network administrator and security specialists thinks of and wants answer. Few days before I read on internet news site that a computer technician accidentally deleted a financial company’s $ 10 billions records. To avoid the big troubles like this for you and for your company, you should have excellent data recovery software in your software inventory. Many data recovery tools are good enough to recover every piece of data if the hard disk is not physically badly damaged.
Network Monitoring Tools
You must have a good network monitoring tools to detect various suspicious things and monitor the various activities in your network such as network traffic, open ports, useless shared folders. GFI LanGuard Network security scanner is a good scanning and monitoring tool and it checks for all the possible methods, which a hacker can use to attack your network.
Internet Access Control
Internet can be a big source of viruses and the major security attacks, if you are unable to implement a tight security policy in your network, if you have a old definition anti virus program and if your haven’t put any check on your network user’s activity. Your gateway or proxy server, which is directly exposed to the internet should have very tight security, updated antivirus program and network monitoring tools.
Information Theft and cryptography attacks
Another threat to a network is to loss of the important information and this loss can be prevented, if you good encryption methods such as 128 bit security or 256 bit security encryption methods. In this way, your data when transferred through FTP programs, can be encrypted and can’t be read or use.
Unauthorized application installations
Another virus and security attack prevention method is to install only the authorized software applications to your network server and your all client computers. Nobody should be allowed to install any kind of program which can cause security threats such as songs or video programs, codec, gaming software or other web based applications.
Security Conclusion:
I tried to point out the major security threat prevention methods also provided the solutions to avoid them. There are a number of ways, which guarantee for the safety and security of your network.
I have summarized the all these method as below.
1. Perform regular network security testing.
2. Don’t provide more or unwanted access to any network user.
3. Must have an updated antivirus program.
4. Operating system should be regularly updated. If you have windows based operating system
you can update it from the Microsoft website.
5. Keep inventory of your network resources such as devices and software applications.
6. Regularly scan TCP/IP services
7. Turn off your computer when you are away and don’t leave your computer unattended.
8. Put a strong network and system administrator password.
9. Implement a strong security policy.
10. Use a switched network, so that you can identify the problem very quickly
A network security threat can be prevented if you have an updated antivirus program, regularly scan all the network devices, emails, open ports, server and client computers. It’s the responsibility of the network administrators to check and deploy the missing security patches in all the network computers. They should also remove the unnecessary network shares, users accounts, wireless access points and restrict the access too the network users. There should be proper training of the network users, network administrators and IT managers about the vulnerable things that cause a network to be attacked. A network administration of an organization should be highly skilled person and have much experience in network/system administration as well as dealing with the security issues.
Security Threats
There are a number of security threats that can be the cause of a network security attack. Main security threats are denial of service, distributed denial of service, viruses, Trojan horses, spywares, malwares, unauthorized access to the network resources and data, accidental deletion of the files and the uncontrolled internet access.
Virus Attack
A computer virus is a small program or an executable code that when executed and replicated, perform different unwanted and harmful functions for a computer and a network. Viruses can destroy your hard disks and processors, consume memory at a very large scale and destroy the overall performance of a computer or network. A Trojan is a malicious code that performs harmful actions but it cannot be replicated. Trojan can destroy systems’ critical data. A computer worm is a program that replicates to all network and destroy useful data. The viruses, malware, adware and Trojan horses can be prevented if you have an updated antivirus program with the latest pattern files.
Security policy
Being a network administrator, you should implement a security policy in your network and educate your network users and other employees about the security threats.
Email scanning
Email is a big source of a virus and malicious code. You should have installed an email scanning and monitoring program. You should also have a tight security policy at your proxy server and should block the unnecessary ports and web applications.
Unauthorized Access
Access to the network resources and data should be allowed only to the authorized persons. Every shared folder and resources in your network should have been accessed only by the authorized persons and should also be scanned and monitored regularly.
Accidental deletion of the files
What will you do if you accidentally delete your organization’s critical data? This is a question, which every network administrator and security specialists thinks of and wants answer. Few days before I read on internet news site that a computer technician accidentally deleted a financial company’s $ 10 billions records. To avoid the big troubles like this for you and for your company, you should have excellent data recovery software in your software inventory. Many data recovery tools are good enough to recover every piece of data if the hard disk is not physically badly damaged.
Network Monitoring Tools
You must have a good network monitoring tools to detect various suspicious things and monitor the various activities in your network such as network traffic, open ports, useless shared folders. GFI LanGuard Network security scanner is a good scanning and monitoring tool and it checks for all the possible methods, which a hacker can use to attack your network.
Internet Access Control
Internet can be a big source of viruses and the major security attacks, if you are unable to implement a tight security policy in your network, if you have a old definition anti virus program and if your haven’t put any check on your network user’s activity. Your gateway or proxy server, which is directly exposed to the internet should have very tight security, updated antivirus program and network monitoring tools.
Information Theft and cryptography attacks
Another threat to a network is to loss of the important information and this loss can be prevented, if you good encryption methods such as 128 bit security or 256 bit security encryption methods. In this way, your data when transferred through FTP programs, can be encrypted and can’t be read or use.
Unauthorized application installations
Another virus and security attack prevention method is to install only the authorized software applications to your network server and your all client computers. Nobody should be allowed to install any kind of program which can cause security threats such as songs or video programs, codec, gaming software or other web based applications.
Security Conclusion:
I tried to point out the major security threat prevention methods also provided the solutions to avoid them. There are a number of ways, which guarantee for the safety and security of your network.
I have summarized the all these method as below.
1. Perform regular network security testing.
2. Don’t provide more or unwanted access to any network user.
3. Must have an updated antivirus program.
4. Operating system should be regularly updated. If you have windows based operating system
you can update it from the Microsoft website.
5. Keep inventory of your network resources such as devices and software applications.
6. Regularly scan TCP/IP services
7. Turn off your computer when you are away and don’t leave your computer unattended.
8. Put a strong network and system administrator password.
9. Implement a strong security policy.
10. Use a switched network, so that you can identify the problem very quickly
Network Security
Introduction to Network Security
You will find here network security overview, networking solutions, anti virus, anti spamming tips, trojan horses, malware, adware. Security is an essential element in maintaining any network. The main focus of the IT managers and computer network administrators is to secure the computer networks.
Users are happy to get the data on time and without any problem. The use of the authentication and biometrics can improve the security to some extend. Computer Security in the data communication cannot be compromised. Hackers’ can exploit the sensitive and financial and corporate data. There can be many threats to a computer network and it’s the responsibility of a computer network administrator to keep the computer network secure from these threats.
IT Administrator should know about all the possible security attacks and also know their solutions. IT Administrator should look for the viruses from the Internet, Malware, Adware, Trojan horses, E-mail attachments, Floppy disk, CD or any infected computer that is attached to the network. Spyware and network intrusions are specifically designed to get the secret information from their target companies, which can do harm for the company. Everyday security threats are refined as hackers designed new security threats.
The main cause of a security threat in the small companies is the misuse of the internet without proper anti virus, anti spyware installed on the every PC of the company’s network. For example if a company’s employees browse an inappropriate website, sends or receives the infected data, leaks company’s secret information, then there are greater chances for a possible virus/malware attack.
In my opinion, the end user’s education on the security threats, preventions and precautionary measures are must. They should be trained about the possible and easy virus attacks from the internet if they browse the inappropriate sites.
Another important thing is the insider’s attack e.g if the company’s employee leave the company for any reason, then its very important that all the computer and other company’s sensitive assets access should be revoked by him immediately. I have personally seen a situation, when a company’s network administrator was dismissed and he access the company’s server by VPN and send harmful viruses to the server and the entire computer network, and it was impossible for the IT manager to control all the security attacks in one time.
It’s the responsibility to keep a closer eye on the new employee’s activities, their access to the sensitive data, and computers servers. IT managers should bring it in the knowledge of the employees that any change in their computer will be logged. So that nobody can even try to do anything that is not permitted.
There are six basic security steps for the Windows platforms. If a network administrator can follow these steps then he/she can save the computerss from all the possible security threats and virus or malware attacks.
First the IT managers should divide the computer network into the segments. They should filter the access to the internet with the help of a firewall by blocking TCP port 1433 and TCP port 1434. Internet access from the outside should be allowed to the SQL systems. All the unwanted ports should be blocked and only the required ports should be open for access.
Second, moderate the affect of the spoofed ports. The port 80 is the most commonly used port.
Third, as network administrator you should install the current patches to you’re your server computer and client’s up to date. Patches can prevent the systems from the known vulnerabilities. Latest patches can be downloaded from the Windows website. You can also configure to automatically update. Also third party patches products are also available that can be tested and installed. Additionally, by strengthening the user authentication process can be very helpful for security purposes.. You can use password security and other technological methods for the authenticate purpose.
Fourth, you can limit the number of the network administrators it can also be helpful for security a computer network. Admin rights should not be given to the local PC, until and unless it is the requirements for the applications that are installed on the local PCs.
Fifth, protect computers against the known attacks. Don’t disable any Windows known service such as clipbook, Telnet etc. Set the powerful permission the shared network resources. Last, you can configure the security policies. Implement the security policies on your network. Security measures and methods have expenses with their purchases. Deployment, maintenance and the implementations of these methods can increase the security cost. Some other things which a IT administrator or a IT manager should keep in mind are the education of the employees about the computer networking, security, use of the encryption and digital right management software, block the unwanted emails and audit security on the regular basis. Network security methods should be used and implemented in order to prevent your computer network from the unauthorized access.
In this article you have discovered the Computer Network Security Overview More topics to come are Cisco Labs, Routing, IP addressing & Free IT resources
You will find here network security overview, networking solutions, anti virus, anti spamming tips, trojan horses, malware, adware. Security is an essential element in maintaining any network. The main focus of the IT managers and computer network administrators is to secure the computer networks.
Users are happy to get the data on time and without any problem. The use of the authentication and biometrics can improve the security to some extend. Computer Security in the data communication cannot be compromised. Hackers’ can exploit the sensitive and financial and corporate data. There can be many threats to a computer network and it’s the responsibility of a computer network administrator to keep the computer network secure from these threats.
IT Administrator should know about all the possible security attacks and also know their solutions. IT Administrator should look for the viruses from the Internet, Malware, Adware, Trojan horses, E-mail attachments, Floppy disk, CD or any infected computer that is attached to the network. Spyware and network intrusions are specifically designed to get the secret information from their target companies, which can do harm for the company. Everyday security threats are refined as hackers designed new security threats.
The main cause of a security threat in the small companies is the misuse of the internet without proper anti virus, anti spyware installed on the every PC of the company’s network. For example if a company’s employees browse an inappropriate website, sends or receives the infected data, leaks company’s secret information, then there are greater chances for a possible virus/malware attack.
In my opinion, the end user’s education on the security threats, preventions and precautionary measures are must. They should be trained about the possible and easy virus attacks from the internet if they browse the inappropriate sites.
Another important thing is the insider’s attack e.g if the company’s employee leave the company for any reason, then its very important that all the computer and other company’s sensitive assets access should be revoked by him immediately. I have personally seen a situation, when a company’s network administrator was dismissed and he access the company’s server by VPN and send harmful viruses to the server and the entire computer network, and it was impossible for the IT manager to control all the security attacks in one time.
It’s the responsibility to keep a closer eye on the new employee’s activities, their access to the sensitive data, and computers servers. IT managers should bring it in the knowledge of the employees that any change in their computer will be logged. So that nobody can even try to do anything that is not permitted.
There are six basic security steps for the Windows platforms. If a network administrator can follow these steps then he/she can save the computerss from all the possible security threats and virus or malware attacks.
First the IT managers should divide the computer network into the segments. They should filter the access to the internet with the help of a firewall by blocking TCP port 1433 and TCP port 1434. Internet access from the outside should be allowed to the SQL systems. All the unwanted ports should be blocked and only the required ports should be open for access.
Second, moderate the affect of the spoofed ports. The port 80 is the most commonly used port.
Third, as network administrator you should install the current patches to you’re your server computer and client’s up to date. Patches can prevent the systems from the known vulnerabilities. Latest patches can be downloaded from the Windows website. You can also configure to automatically update. Also third party patches products are also available that can be tested and installed. Additionally, by strengthening the user authentication process can be very helpful for security purposes.. You can use password security and other technological methods for the authenticate purpose.
Fourth, you can limit the number of the network administrators it can also be helpful for security a computer network. Admin rights should not be given to the local PC, until and unless it is the requirements for the applications that are installed on the local PCs.
Fifth, protect computers against the known attacks. Don’t disable any Windows known service such as clipbook, Telnet etc. Set the powerful permission the shared network resources. Last, you can configure the security policies. Implement the security policies on your network. Security measures and methods have expenses with their purchases. Deployment, maintenance and the implementations of these methods can increase the security cost. Some other things which a IT administrator or a IT manager should keep in mind are the education of the employees about the computer networking, security, use of the encryption and digital right management software, block the unwanted emails and audit security on the regular basis. Network security methods should be used and implemented in order to prevent your computer network from the unauthorized access.
In this article you have discovered the Computer Network Security Overview More topics to come are Cisco Labs, Routing, IP addressing & Free IT resources
Windows 2000 Professional On Network
Installing Windows 2000 Professional
In this section you will learn how to install Windows 2000 Professional. This tutorial covers the basic steps, which are required for the installation and configurations. There are different methods of installing the Windows 2000 Professional.There are two basic types of the installation.
1. Fresh Installation
2. Dual Boot Installation
In the fresh installation method, Windows 2000 is installed as the only operating system on a
formatted or empty hard disk. In the dual boot installation method Windows 2000 Professional is installed alongside another operating system on the same hard disk such as Windows NT, Windows XP, Windows 98 or Red hat Linux. All the operating systems are needed to be installed on the separate portions of the hard disk.
Just start from the Windows 2000 Professional installation CD. Make sure that your computer is set to boot from the CD first. To get the grip on Windows 2000 Professional installation and for easy to understand, I have discussed all the installation methods in the following points.
1. Insert the Windows 2000 Professional in the CD-ROM and start the computer and when you
are prompted press any key to start the Windows 2000 Professional setup program.
2. Start from the boot disks, insert the disk first and then remaining three floppies when you
prompted.
3. Insert the CD-ROM and then at the command prompt type drive:\1386\winnt32.exe and
then press Enter or if there is no previous installation on this computer then type drive:\i386
\winnt.exe and press Enter, where drives a letter of your CD-ROM drive. Setup starts and
begins to inspect your computer’s hardware configurations and load device drivers and
other necessary installation files.
4. Press Enter when Microsoft Windows 2000 Professional screen appear.
5. Press F8 to accept the license agreement and continue the installation.
6. Next either creates a new partition by pressing C and deletes the old partitions.
7. Format the partition by using the FAT 32 or NTFS file system and press Enter.
8. Setup formats the partition by the file system you selected and then begins to copy the
installation files on your selected drive. After all the installation files copies in the first step,
system restarts.
9. After the first restart, GUI interface starts click next to continue the setup. Setup detects and
installs the device drivers of specialized mouse and keyboard.
10. When the regional settings appear customize your installation for locale, format, number,
currency, time, date and language if necessary. After this does not press start from CD-ROM
when your computer restarts.
11. In the personalize dialog box, type your name and your company name. In the product ID
dialog box type 25 character key. Press next in the computer name and password dialog box,
either accept the default computer name or assign a customize computer name. You can set
the password for the local administrator account.
12. In the date and time settings, select the correct data and time. Here you can also specify
which time zone you are in, and set the computer to automatically adjust the clock for
daylight saving time.
13. Click next setup will detect the networking software and settings, either select the typical to
set default network settings for File and print sharing for Microsoft networks or choose the
customized settings for your network such as IP address, workgroup or domain name, DHCP
server settings etc.
14. During the final stage of installation, setup installs start menu items, registers components,
saves settings and removes the temporary files, which were created during the installation.
When Completing Windows 2000 Setup Wizard dialog box appears, remove the CD from the
CD-ROM and click finish to restart the computer.
15. After the computer restarts, click next in the Welcome to the Network Identification Wizard
dialog box. In the users of this computer dialog box, either specifies that user musts enter
user name and passwords or select Window 2000 Profession should automatically log on a
specific user. Click finish.
In this tutorial, I have covered the basic steps, necessary to install Windows 2000
Professional. You can find the separate tutorials on how to create the Boot Disks, which are
necessary for the installing the Windows 2000. You have the option to skip the boot disk creating portion. You can even install the windows without inserting the floppy disks for creating the boot disks
In this section you will learn how to install Windows 2000 Professional. This tutorial covers the basic steps, which are required for the installation and configurations. There are different methods of installing the Windows 2000 Professional.There are two basic types of the installation.
1. Fresh Installation
2. Dual Boot Installation
In the fresh installation method, Windows 2000 is installed as the only operating system on a
formatted or empty hard disk. In the dual boot installation method Windows 2000 Professional is installed alongside another operating system on the same hard disk such as Windows NT, Windows XP, Windows 98 or Red hat Linux. All the operating systems are needed to be installed on the separate portions of the hard disk.
Just start from the Windows 2000 Professional installation CD. Make sure that your computer is set to boot from the CD first. To get the grip on Windows 2000 Professional installation and for easy to understand, I have discussed all the installation methods in the following points.
1. Insert the Windows 2000 Professional in the CD-ROM and start the computer and when you
are prompted press any key to start the Windows 2000 Professional setup program.
2. Start from the boot disks, insert the disk first and then remaining three floppies when you
prompted.
3. Insert the CD-ROM and then at the command prompt type drive:\1386\winnt32.exe and
then press Enter or if there is no previous installation on this computer then type drive:\i386
\winnt.exe and press Enter, where drives a letter of your CD-ROM drive. Setup starts and
begins to inspect your computer’s hardware configurations and load device drivers and
other necessary installation files.
4. Press Enter when Microsoft Windows 2000 Professional screen appear.
5. Press F8 to accept the license agreement and continue the installation.
6. Next either creates a new partition by pressing C and deletes the old partitions.
7. Format the partition by using the FAT 32 or NTFS file system and press Enter.
8. Setup formats the partition by the file system you selected and then begins to copy the
installation files on your selected drive. After all the installation files copies in the first step,
system restarts.
9. After the first restart, GUI interface starts click next to continue the setup. Setup detects and
installs the device drivers of specialized mouse and keyboard.
10. When the regional settings appear customize your installation for locale, format, number,
currency, time, date and language if necessary. After this does not press start from CD-ROM
when your computer restarts.
11. In the personalize dialog box, type your name and your company name. In the product ID
dialog box type 25 character key. Press next in the computer name and password dialog box,
either accept the default computer name or assign a customize computer name. You can set
the password for the local administrator account.
12. In the date and time settings, select the correct data and time. Here you can also specify
which time zone you are in, and set the computer to automatically adjust the clock for
daylight saving time.
13. Click next setup will detect the networking software and settings, either select the typical to
set default network settings for File and print sharing for Microsoft networks or choose the
customized settings for your network such as IP address, workgroup or domain name, DHCP
server settings etc.
14. During the final stage of installation, setup installs start menu items, registers components,
saves settings and removes the temporary files, which were created during the installation.
When Completing Windows 2000 Setup Wizard dialog box appears, remove the CD from the
CD-ROM and click finish to restart the computer.
15. After the computer restarts, click next in the Welcome to the Network Identification Wizard
dialog box. In the users of this computer dialog box, either specifies that user musts enter
user name and passwords or select Window 2000 Profession should automatically log on a
specific user. Click finish.
In this tutorial, I have covered the basic steps, necessary to install Windows 2000
Professional. You can find the separate tutorials on how to create the Boot Disks, which are
necessary for the installing the Windows 2000. You have the option to skip the boot disk creating portion. You can even install the windows without inserting the floppy disks for creating the boot disks
Windows 2000 Server Installation
Windows 2000 Server Installation Overview
In this section you will learn the basicss of windows 2000 server installation, how to install window, active directory, domain controllers, system configurations. Being a network administrator or Microsoft Windows 2000 Server support professional, one of your job description tasks is Windows Server Installation.
Step #1: Planning for your installation
When you run the Windows 2000 Server setup program you must know that how to install the Windows 2000 server. Thorough planning can make you avoid potential problems during the installation process. So, it’s necessary to do some paper work and make a good plan before installing the Windows 2000 server operating system. You must know the needs of your office network, server hardware and software to be installed on your server.
Without a proper plan Potential problems can occur in the future and work can become more hectic. There are some important points, which you should take into account before starting the installation process.
1. Check System requirement
2. Check hardware and software compatibility
3. Check the disk partitioning options
4. Select the file systems according to your needs.
5. Decide workgroup or domain installation
6. Complete a pre installation checklist.Once you are making sure about these things you can
start the installation process.
Step #2: Starting the installation process
You can install Windows 2000 Server in different ways, all the methods are valid and which method you choose is depends on your needs and limitations. Manual installation process can be divided into different ways as followings.
• Boot from CD- This is a fresh installation and no existing partition is required.
• Boot from the 4 setup disks and then insert the CD, in this way also not existing partition is
required.
• Boot from an MS-DOS startup floppy disk, go to the command prompt, create a 4GB FAT32
partition with FDISK command, reboot the computer, format the C partition, you have created
and then go to the CD drive, go to the i386 folder and run the Winnt.exe command.
• In the other methods, run an already installed operating system such as Windows NT 4.0
Server and from within the NT 4.0 go to the i386 folder in the Windows 2000 Server
installation CD and run the WINNT32.exe command. This will upgrade the Windows NT
Server 4.0 to the Windows 2000 Server.
• Alternatively, if you want to upgrade from Windows 98 into Windows 2000 Professional you
can follow the same steps as I have described in the above installation method. But you cannot
upgrade Windows 98 into Windows 2000 server.
Additionally, there are other automated installation methods, such as uninstallation method by using an unattended file, using Sysprep, using RIS or running the uninstallation method by the CD itself.
It doesn’t matter that which installation method you use to install Windows 2000 Server or Professional. All methods look alike and the main function is the same.
Step #3: Text based portion of the setup
The setup process starts loading a blue-looking text screen. In this way you will be asked to accept the license agreement EULA and choose a partition on which you want to install Windows 2000 and you will be also asked to format the partition if the partition is new FAT, FAT32 or NTFS. The setup process begins loading a blue-looking text screen (not GUI).
1. Select to boot the computer from CD.
2. At this stage you can press F6 if you need to install the additional SCSI adapters or other
storage devices. If you choose it then you will be asked to provide the floppy disk for the
drivers.
3. Setup will get all the required drivers and files.
4. Now select to setup Windows 2000. At this point, if you want to fix some problems in the
previously installed operating systems then you will have to press R. If not, then just press
enter to continue with the fresh installation.
5. If you haven’t made any partition then you will get a warning message to create a partition
and delete the old partitions. You can specify the partition size here. If you want to continue
then press C.
6. Accept the license agreement and pressF8.
•Select or create the partition on which you will install W2K.
•If you hard disk is already partitioned but don’t have enough disk space for the installation,
you can create an additional partition from the unpartitioned space. If the hard disk is already
partitioned, but has enough unpartitioned disk space, you can create an additional partition in
the unpartitioned space. If the hard disk already has a existing partition, you can delete it to
create more unpartitioned space for the new partition. By deleting the old partition you will
delete all data on that partition.
If you select a new partition during Setup, create and size only the partition on which you will
install Windows 2000. After installation, use Disk Management to partition the remaining
space on the hard disk.
7. Select the file system like FAT32, NTFS for the installation partition. After you create the
partition, select a file system. After selecting the file system, it will ask you to format the disk.
Windows 2000 supports FAT, FAT32 and NTFS file system. You can get access to the local
data on your hard disk, if it is formatted with the NTFS and if your operating system is
Windows Server 2003, Windows XP Professional, Windows 2000 and Windows NT. If you
plan to get data on your local hard disk’s drive where Windows 95 or Windows 98 is installed
then you will have to use FAT or FAT32 file systems.
8. Setup will then begin copying files after formatting the disk, from the installation point (CD,
local i386 or a network share).
9. After copying files step is completed the computer will be restarted in the graphical mode.
Step #4: Graphical user interface (GUI) based setup portion
After the first reboot and copying the necessary installation files the setup comes in the graphical mode.
Next it will load the device drivers based on the hardware it finds in your computer. At this point, you can change the regional settings if you want.
1. Install the Hebrew language support at this point.
2. Here type your name and organization name.
3. Next type product key.
4. Enter the appropriate license types and the number of the purchased licenses.
5. Here you type the computer name and the password of the local administrator account.
The local administrator account is based in the SAM of the computer and is used for the
locally administrative tasks4. Next choose which network or other components to be installed
on the system.
6. Next select the date, time and zone settings.
7. Setup now will install the networking components. Press Next to accept the typical settings
option if you have one of the following situations:
• You have DHCP on your network.
• Your computer running Internet Connection Sharing (ICS).
• You are in a workgroup environment and do not plan to have any other servers or Active
Directory at all, and all other workgroup members are configured in the same manner.
Otherwise select Custom Settings and press Next to customize your network settings.
8. You should highlight the TCP/IP section and press Properties.In the following general tab
enter the necessary information. You should specify the IP address, and if you don't know
what the Subnet Mask entry should be - you can simply place your mouse pointer over the
empty area in the Subnet Mask box and click it. The operating system will automatically
detect the settings.
If you are a stand alone computer or you don’t have the sufficient rights, leave the default
entry selected and press next.
9. In the next stage setup process will finish copying files and configuring the setup.
10. Next the setup process finishes and displays the finish window.
11. Next Windows 2000 reboots and you after reboot you get the CTRL-ALT-DEL window.
12. Congratulations. You are done. Windows 2000 has been installed on you computer.
In this section you will learn the basicss of windows 2000 server installation, how to install window, active directory, domain controllers, system configurations. Being a network administrator or Microsoft Windows 2000 Server support professional, one of your job description tasks is Windows Server Installation.
Step #1: Planning for your installation
When you run the Windows 2000 Server setup program you must know that how to install the Windows 2000 server. Thorough planning can make you avoid potential problems during the installation process. So, it’s necessary to do some paper work and make a good plan before installing the Windows 2000 server operating system. You must know the needs of your office network, server hardware and software to be installed on your server.
Without a proper plan Potential problems can occur in the future and work can become more hectic. There are some important points, which you should take into account before starting the installation process.
1. Check System requirement
2. Check hardware and software compatibility
3. Check the disk partitioning options
4. Select the file systems according to your needs.
5. Decide workgroup or domain installation
6. Complete a pre installation checklist.Once you are making sure about these things you can
start the installation process.
Step #2: Starting the installation process
You can install Windows 2000 Server in different ways, all the methods are valid and which method you choose is depends on your needs and limitations. Manual installation process can be divided into different ways as followings.
• Boot from CD- This is a fresh installation and no existing partition is required.
• Boot from the 4 setup disks and then insert the CD, in this way also not existing partition is
required.
• Boot from an MS-DOS startup floppy disk, go to the command prompt, create a 4GB FAT32
partition with FDISK command, reboot the computer, format the C partition, you have created
and then go to the CD drive, go to the i386 folder and run the Winnt.exe command.
• In the other methods, run an already installed operating system such as Windows NT 4.0
Server and from within the NT 4.0 go to the i386 folder in the Windows 2000 Server
installation CD and run the WINNT32.exe command. This will upgrade the Windows NT
Server 4.0 to the Windows 2000 Server.
• Alternatively, if you want to upgrade from Windows 98 into Windows 2000 Professional you
can follow the same steps as I have described in the above installation method. But you cannot
upgrade Windows 98 into Windows 2000 server.
Additionally, there are other automated installation methods, such as uninstallation method by using an unattended file, using Sysprep, using RIS or running the uninstallation method by the CD itself.
It doesn’t matter that which installation method you use to install Windows 2000 Server or Professional. All methods look alike and the main function is the same.
Step #3: Text based portion of the setup
The setup process starts loading a blue-looking text screen. In this way you will be asked to accept the license agreement EULA and choose a partition on which you want to install Windows 2000 and you will be also asked to format the partition if the partition is new FAT, FAT32 or NTFS. The setup process begins loading a blue-looking text screen (not GUI).
1. Select to boot the computer from CD.
2. At this stage you can press F6 if you need to install the additional SCSI adapters or other
storage devices. If you choose it then you will be asked to provide the floppy disk for the
drivers.
3. Setup will get all the required drivers and files.
4. Now select to setup Windows 2000. At this point, if you want to fix some problems in the
previously installed operating systems then you will have to press R. If not, then just press
enter to continue with the fresh installation.
5. If you haven’t made any partition then you will get a warning message to create a partition
and delete the old partitions. You can specify the partition size here. If you want to continue
then press C.
6. Accept the license agreement and pressF8.
•Select or create the partition on which you will install W2K.
•If you hard disk is already partitioned but don’t have enough disk space for the installation,
you can create an additional partition from the unpartitioned space. If the hard disk is already
partitioned, but has enough unpartitioned disk space, you can create an additional partition in
the unpartitioned space. If the hard disk already has a existing partition, you can delete it to
create more unpartitioned space for the new partition. By deleting the old partition you will
delete all data on that partition.
If you select a new partition during Setup, create and size only the partition on which you will
install Windows 2000. After installation, use Disk Management to partition the remaining
space on the hard disk.
7. Select the file system like FAT32, NTFS for the installation partition. After you create the
partition, select a file system. After selecting the file system, it will ask you to format the disk.
Windows 2000 supports FAT, FAT32 and NTFS file system. You can get access to the local
data on your hard disk, if it is formatted with the NTFS and if your operating system is
Windows Server 2003, Windows XP Professional, Windows 2000 and Windows NT. If you
plan to get data on your local hard disk’s drive where Windows 95 or Windows 98 is installed
then you will have to use FAT or FAT32 file systems.
8. Setup will then begin copying files after formatting the disk, from the installation point (CD,
local i386 or a network share).
9. After copying files step is completed the computer will be restarted in the graphical mode.
Step #4: Graphical user interface (GUI) based setup portion
After the first reboot and copying the necessary installation files the setup comes in the graphical mode.
Next it will load the device drivers based on the hardware it finds in your computer. At this point, you can change the regional settings if you want.
1. Install the Hebrew language support at this point.
2. Here type your name and organization name.
3. Next type product key.
4. Enter the appropriate license types and the number of the purchased licenses.
5. Here you type the computer name and the password of the local administrator account.
The local administrator account is based in the SAM of the computer and is used for the
locally administrative tasks4. Next choose which network or other components to be installed
on the system.
6. Next select the date, time and zone settings.
7. Setup now will install the networking components. Press Next to accept the typical settings
option if you have one of the following situations:
• You have DHCP on your network.
• Your computer running Internet Connection Sharing (ICS).
• You are in a workgroup environment and do not plan to have any other servers or Active
Directory at all, and all other workgroup members are configured in the same manner.
Otherwise select Custom Settings and press Next to customize your network settings.
8. You should highlight the TCP/IP section and press Properties.In the following general tab
enter the necessary information. You should specify the IP address, and if you don't know
what the Subnet Mask entry should be - you can simply place your mouse pointer over the
empty area in the Subnet Mask box and click it. The operating system will automatically
detect the settings.
If you are a stand alone computer or you don’t have the sufficient rights, leave the default
entry selected and press next.
9. In the next stage setup process will finish copying files and configuring the setup.
10. Next the setup process finishes and displays the finish window.
11. Next Windows 2000 reboots and you after reboot you get the CTRL-ALT-DEL window.
12. Congratulations. You are done. Windows 2000 has been installed on you computer.
Basic Network Troubleshooting
Basic Network Troubleshooting
Here you will learn network troubleshooting tips, fix tcp/ip errors, tcp/ip settings, internet connectivity errors, how to fix pc errors, lan connectivity issues, traceroute and ping commands. Whether your operating system is Windows or Linux network problems are likely to arise. Many times the network problems arisee due to improperly configured TCP/IP settings. Following is the basic checklist to identify and troubleshoot the basic networking errors.
1. First of all you should learn what stopped working server or client computer also see if the
outage affecting the other computers or only one.
2. If you server stopped working you should inform the users of the server and you should start
working on fixing the error.
3. If a single client computer stopped working or disconnected from the network, ask the user of
that computer that what recent changes cause the server to stop working such as newly
installed software or games, service pakcs, internet software, new hardware or any other
thing.
4. Check the physical network connectivity. The most network problems arise due to the
physical layers failure.
5. Check all the network cable connections. You can start at the NIC and check if the green light
is blinking then check the hub and see if the computer is getting the link across the cable.
6. Get a cable tester to check the connectivity of the cables.
7. Finally start pinging the network both Windows and Linux have the PING command. You can
use ping command in this way start > Run > cmd > type "ping" then IP address of the other
computer.
How to Troubleshoot Connectivity problems
1. Use the ping command to test the basic connectivity. By using the ping command you can
isolate network hardware problems and incompatible configurations. By using the path ping
you can detect packet loss.
2. If you want to see the Ping's statistics then you ping -t command and press enter to continue
and if you want to stop then press CTRL+BREAKTo watch Ping statistics, use the ping -t
command. To see statistics and continue, press CTRL+BREAK. To stop, press CTRL+C.
3. If you remote system is across the delay link, such as satellite link responses may take
longer.
4. Check the event logs for network card and other hardware and software configurations and
connectivity related entries.
5. Check whether the NIC card is on the Microsoft Hardware Compatibility List (HCL).
6. Check other computers that use the same gateway and are plugged into the same hub or
switch and if these computers do not show any network connectivity problem then the
problem is on the only one computer.
7. Contact the vendor of each NIC and motherboard and update the BIOS.
8. Replace the network adapter of the system with the good configured system and see if the
same error arise again.
SOME BASIC TROUBLESHOOTING TIPS
Make sure that you have the same IP address schme, same subnet mask, same default gateway, same DNS and DHCP settings for all the computers in a network. Also make sure that you can ping the other computers by their IP address as well as by their name. Make sure that you have the same workgroup or domain name for all the computers. For troubleshooting and administrative purposes turn off all the firewalls. Use the same administrative password for troubleshooting on all the computers. Try pinging the other computers this will test the TCP/IP connectivity. You can use the ping command in this format ping 10.100.100.1 and if you can get the reply from the other computer then the connectivity is ok and if get the time out error then there must me some error in the connectivity or error in configurations.
Issues in Finding websites
If you find any problem in finding the websites then ping the website name rather than the IP address and this will determine if your DNS entry is corret or working for example ping www.google.com. If this works then problem must be in your web browser due to misconfigurations. You should check the proxy server settings of your browsers and clear the cache and temporary internet files. Issues in Pinging a computerIf you can't ping the computer by its name then check the DNS IP address in your network or dial-up setup.
Issues in connecting to the other device on Local Area Network
If you can ping all the other computers but are not allowed access then make sure that you are using the same user name and password assigned by the same domain controller. Try connecting to the computer using start > run > server name where serve name is the name of the server you want to connect to. Also add the computer name and it's IP address in the LMHOSTS file, which resides at Windows\System32\Drivers directory for Windows 2000 or XP.
Issues in Network Connectivity.
If a computer is unable to connect to a network or see other computers in a network it may be necessary to troubleshoot the network. Due to the following reasons you network may not work.
1. Network card not connected properly
2. Bad NIC card drive's settings
3. Firewall preventing computers from seeing each other.
4. Connection related issues.
5. Bad network hardware.
Solution:
Because of the large variety of the network configurations, setup, software, hardware operating systems etc not all the information may apply to your network or operating system. First of all verify that the network cable of each computer is properly connected, one end to the NIC card, which is plugged into the computer and one end to the Hub or switch. Ensure that the green light is blinking on the NIC, this shows that the NIC is either receiving or sending the data. On the other hand if the card does not have any lights or has orange or red lights, then is possible that either the NIC adapter is bad or not connected properly.
Make sure that the cables are properly connected to the hub or swtich. Make sure that the newly installed NIC adapter is not conflicting with the other NIC cards on the network and a unique IP address is assigned to each NIC card. If there is some conflict then the device manager may identify the conflicting card. Furthermore, make sure that the NIC is capable of pinging or seeing itself by the ping command. If you are on the TCP/IP network, make sure that the correct protocols are installed. If you are using a firewall, ensure all the ports required are open. While troubleshooting you can close the firewall program so that they there should not occur any conflict.
TCP/IP Configuraitons Checking
The first step in the troubleshooting process is to check the TCP/IP settings. You can check it by using the IPCONFIG/All command on the command prompt. You will see the configuration results. If you see a blank configuration for a card this means then the card is not assigned any IP address. You can assign the IP address manually or via DHCP server. If you are using the DHCP server for assigning the IP addresses then you can use the following commands to get and release the IP address.
IPConfig/Release
IPConfig/Renew
IPConfig/All
If the computer is still unalbe to obtain an IP address, then there are several things that can causing this problem such as bad network cable or NIC card, DHCP server might have assigned all the IP addresses from its pool, misconfigured TCP/IP settings, incorrect user name and password. You can try to add a new well configured machine to the replace the malfunctioning machine to see if the new machine is working with its settings. Also see if the driver of the NIC is properly installed or not. In case of driver's problem go to the vendor's website and install a new exact driver for the NIC.
Network Software Overview & General System Admin Utilities
This section provides the overview of the network software such as free LAN/WAN tools, tutorials and labs, LAN troubleshooter, WAN optimizer, sniffer, traceroute, IP finder, whois lookup, administration, LAN security, Admin tools & proxy server software, protocol analyzers, remote computing, FTP software and many others.
Software or program enables a computer to perform the specified tasks. This includes the application software such as Win word and system software like operating systems.
A network is made up of two ore more computers that are linked together either wired or wireless to share data and resources and network can also be used to transmit information from one computer to another, to play games to talk to a friend and to share a common network resource. Network software is the information, programming or data used to make it possible for a computer to communicate with other computers or devices.
IP Addressing Utilities
If you are on the dial-up connection your IP address usually changes every time when you connect to the internet in case of (dynamic IP) and thus makes it difficult for the people to connect directly to your machine.
Misc. Communication Tools
In this category you will find various internet/network tools and utilities that are not fit in any other category.
Network Administration
Here you will be able to find the tools necessary for the network administrator to manage their networking tasks such as auditing, LAN troubleshooting, deployment and remote control panel tools.
Communication Information
Here you will find various system admin related utilities like Ping, Trace Router, Finger, WhoIs, IP finder and many others.
Communication Monitoring
This is a collection of the best tools to monitor the performance of a network servers, clients or Internet servers and communication device.
Domain Lookup Tools
Here you will find the details about the owner of a website and you can also search for the available domain names by different keywords and other criteria.
Newsreaders/Usenet
The Newsgroups are like the electronic bulletin boards to share the information and the tools in
this category will allow you to connect and manage the contents.
Protocol Analyzers
Protocols analyzers are referred to as Packet Sniffers. The tools in this category will allow you to analyze your network traffic with different graphical overview, monitoring and also troubleshootingof the devices.
Proxy Server Software
The proxy servers allow you to share control and filter the internet connection. Proxy serves also
act as the internet gateway for your LAN.
FTP Programs
FTP is a file transfer protocol, which allows you to connect to other computers and download or upload the files. You can connect to your FTP server, where you have hosted your website through FTP client program such as FTP voyager, AceFTP, CuteFTP and other. In this category
you will find various FTP related .
Traffic Scanner Tools
These tools will allow you to scan your network, open ports and for the possible virus threats,
security breaches and other vulnerabilities. Here you will find a list of the traffic tester software.
Communication Testing
If you want to test your network or web applications, connectivity, check performance and simulate user activities then you can find a list of the software here in this category.
Tools & Suites
The Tool suites that combine a popular computer networking tools such as PING, Finger, Traceroute and many other tools.
Remote Computing
In this list of software you will be able to connect to the remote computer and you can share data, file and documents and even you will software for the remote administration purposes.
Telnet & SSH Clients
Here is a list of the various clients’ software that allows you to connect to a computer using the Telnet protocol.
Time Synchronization Tools
These software will allow your PC’s time to Synchronize with the atomic clocks over the Internet.Trace route Utilities
Traceroute utilities will allow you to determine the origin and path of the connection. Some of the tools even provide the detailed geographical information on a globe map, allowing you to trace the location of a server or user.
Here you will learn network troubleshooting tips, fix tcp/ip errors, tcp/ip settings, internet connectivity errors, how to fix pc errors, lan connectivity issues, traceroute and ping commands. Whether your operating system is Windows or Linux network problems are likely to arise. Many times the network problems arisee due to improperly configured TCP/IP settings. Following is the basic checklist to identify and troubleshoot the basic networking errors.
1. First of all you should learn what stopped working server or client computer also see if the
outage affecting the other computers or only one.
2. If you server stopped working you should inform the users of the server and you should start
working on fixing the error.
3. If a single client computer stopped working or disconnected from the network, ask the user of
that computer that what recent changes cause the server to stop working such as newly
installed software or games, service pakcs, internet software, new hardware or any other
thing.
4. Check the physical network connectivity. The most network problems arise due to the
physical layers failure.
5. Check all the network cable connections. You can start at the NIC and check if the green light
is blinking then check the hub and see if the computer is getting the link across the cable.
6. Get a cable tester to check the connectivity of the cables.
7. Finally start pinging the network both Windows and Linux have the PING command. You can
use ping command in this way start > Run > cmd > type "ping" then IP address of the other
computer.
How to Troubleshoot Connectivity problems
1. Use the ping command to test the basic connectivity. By using the ping command you can
isolate network hardware problems and incompatible configurations. By using the path ping
you can detect packet loss.
2. If you want to see the Ping's statistics then you ping -t command and press enter to continue
and if you want to stop then press CTRL+BREAKTo watch Ping statistics, use the ping -t
command. To see statistics and continue, press CTRL+BREAK. To stop, press CTRL+C.
3. If you remote system is across the delay link, such as satellite link responses may take
longer.
4. Check the event logs for network card and other hardware and software configurations and
connectivity related entries.
5. Check whether the NIC card is on the Microsoft Hardware Compatibility List (HCL).
6. Check other computers that use the same gateway and are plugged into the same hub or
switch and if these computers do not show any network connectivity problem then the
problem is on the only one computer.
7. Contact the vendor of each NIC and motherboard and update the BIOS.
8. Replace the network adapter of the system with the good configured system and see if the
same error arise again.
SOME BASIC TROUBLESHOOTING TIPS
Make sure that you have the same IP address schme, same subnet mask, same default gateway, same DNS and DHCP settings for all the computers in a network. Also make sure that you can ping the other computers by their IP address as well as by their name. Make sure that you have the same workgroup or domain name for all the computers. For troubleshooting and administrative purposes turn off all the firewalls. Use the same administrative password for troubleshooting on all the computers. Try pinging the other computers this will test the TCP/IP connectivity. You can use the ping command in this format ping 10.100.100.1 and if you can get the reply from the other computer then the connectivity is ok and if get the time out error then there must me some error in the connectivity or error in configurations.
Issues in Finding websites
If you find any problem in finding the websites then ping the website name rather than the IP address and this will determine if your DNS entry is corret or working for example ping www.google.com. If this works then problem must be in your web browser due to misconfigurations. You should check the proxy server settings of your browsers and clear the cache and temporary internet files. Issues in Pinging a computerIf you can't ping the computer by its name then check the DNS IP address in your network or dial-up setup.
Issues in connecting to the other device on Local Area Network
If you can ping all the other computers but are not allowed access then make sure that you are using the same user name and password assigned by the same domain controller. Try connecting to the computer using start > run > server name where serve name is the name of the server you want to connect to. Also add the computer name and it's IP address in the LMHOSTS file, which resides at Windows\System32\Drivers directory for Windows 2000 or XP.
Issues in Network Connectivity.
If a computer is unable to connect to a network or see other computers in a network it may be necessary to troubleshoot the network. Due to the following reasons you network may not work.
1. Network card not connected properly
2. Bad NIC card drive's settings
3. Firewall preventing computers from seeing each other.
4. Connection related issues.
5. Bad network hardware.
Solution:
Because of the large variety of the network configurations, setup, software, hardware operating systems etc not all the information may apply to your network or operating system. First of all verify that the network cable of each computer is properly connected, one end to the NIC card, which is plugged into the computer and one end to the Hub or switch. Ensure that the green light is blinking on the NIC, this shows that the NIC is either receiving or sending the data. On the other hand if the card does not have any lights or has orange or red lights, then is possible that either the NIC adapter is bad or not connected properly.
Make sure that the cables are properly connected to the hub or swtich. Make sure that the newly installed NIC adapter is not conflicting with the other NIC cards on the network and a unique IP address is assigned to each NIC card. If there is some conflict then the device manager may identify the conflicting card. Furthermore, make sure that the NIC is capable of pinging or seeing itself by the ping command. If you are on the TCP/IP network, make sure that the correct protocols are installed. If you are using a firewall, ensure all the ports required are open. While troubleshooting you can close the firewall program so that they there should not occur any conflict.
TCP/IP Configuraitons Checking
The first step in the troubleshooting process is to check the TCP/IP settings. You can check it by using the IPCONFIG/All command on the command prompt. You will see the configuration results. If you see a blank configuration for a card this means then the card is not assigned any IP address. You can assign the IP address manually or via DHCP server. If you are using the DHCP server for assigning the IP addresses then you can use the following commands to get and release the IP address.
IPConfig/Release
IPConfig/Renew
IPConfig/All
If the computer is still unalbe to obtain an IP address, then there are several things that can causing this problem such as bad network cable or NIC card, DHCP server might have assigned all the IP addresses from its pool, misconfigured TCP/IP settings, incorrect user name and password. You can try to add a new well configured machine to the replace the malfunctioning machine to see if the new machine is working with its settings. Also see if the driver of the NIC is properly installed or not. In case of driver's problem go to the vendor's website and install a new exact driver for the NIC.
Network Software Overview & General System Admin Utilities
This section provides the overview of the network software such as free LAN/WAN tools, tutorials and labs, LAN troubleshooter, WAN optimizer, sniffer, traceroute, IP finder, whois lookup, administration, LAN security, Admin tools & proxy server software, protocol analyzers, remote computing, FTP software and many others.
Software or program enables a computer to perform the specified tasks. This includes the application software such as Win word and system software like operating systems.
A network is made up of two ore more computers that are linked together either wired or wireless to share data and resources and network can also be used to transmit information from one computer to another, to play games to talk to a friend and to share a common network resource. Network software is the information, programming or data used to make it possible for a computer to communicate with other computers or devices.
IP Addressing Utilities
If you are on the dial-up connection your IP address usually changes every time when you connect to the internet in case of (dynamic IP) and thus makes it difficult for the people to connect directly to your machine.
Misc. Communication Tools
In this category you will find various internet/network tools and utilities that are not fit in any other category.
Network Administration
Here you will be able to find the tools necessary for the network administrator to manage their networking tasks such as auditing, LAN troubleshooting, deployment and remote control panel tools.
Communication Information
Here you will find various system admin related utilities like Ping, Trace Router, Finger, WhoIs, IP finder and many others.
Communication Monitoring
This is a collection of the best tools to monitor the performance of a network servers, clients or Internet servers and communication device.
Domain Lookup Tools
Here you will find the details about the owner of a website and you can also search for the available domain names by different keywords and other criteria.
Newsreaders/Usenet
The Newsgroups are like the electronic bulletin boards to share the information and the tools in
this category will allow you to connect and manage the contents.
Protocol Analyzers
Protocols analyzers are referred to as Packet Sniffers. The tools in this category will allow you to analyze your network traffic with different graphical overview, monitoring and also troubleshootingof the devices.
Proxy Server Software
The proxy servers allow you to share control and filter the internet connection. Proxy serves also
act as the internet gateway for your LAN.
FTP Programs
FTP is a file transfer protocol, which allows you to connect to other computers and download or upload the files. You can connect to your FTP server, where you have hosted your website through FTP client program such as FTP voyager, AceFTP, CuteFTP and other. In this category
you will find various FTP related .
Traffic Scanner Tools
These tools will allow you to scan your network, open ports and for the possible virus threats,
security breaches and other vulnerabilities. Here you will find a list of the traffic tester software.
Communication Testing
If you want to test your network or web applications, connectivity, check performance and simulate user activities then you can find a list of the software here in this category.
Tools & Suites
The Tool suites that combine a popular computer networking tools such as PING, Finger, Traceroute and many other tools.
Remote Computing
In this list of software you will be able to connect to the remote computer and you can share data, file and documents and even you will software for the remote administration purposes.
Telnet & SSH Clients
Here is a list of the various clients’ software that allows you to connect to a computer using the Telnet protocol.
Time Synchronization Tools
These software will allow your PC’s time to Synchronize with the atomic clocks over the Internet.Trace route Utilities
Traceroute utilities will allow you to determine the origin and path of the connection. Some of the tools even provide the detailed geographical information on a globe map, allowing you to trace the location of a server or user.
Optical Networks
What is a Optical Network?
In this general optical network tutorial you will find basic overview of the fiber optic technology, communication glossary, lan/wan cables, communication devices and the fiber optic industry trends.. Optical network is a network of the fiber optics cables in which data travels on the thin fibers at the speed of the light. Today, many ISPs, corporate offices, LANS and even home networks are connected through the fiber optics though it’s still very costly but it provides a high bandwidth and data transfer capacity. Fiber optic cables act as a backbone when they connect different ISPs with each other and in case of any breakdown or any kind of problem in the backbone results in a communication failure at very large scale. There are a large number of the fiber optic cables are involved in making the whole internet.
Fiber Optic Technology
Fiber optic technology is most popular in the telecommunication industries as well as Local Area networks. Fiber optic cable is a bundle of various cables which are thin and provides a large bandwidth. The cost of the fiber optic cables is much higher and same is the installation of the fiber optic cables. Today, a large number of the communication networks depend on the fiber optics. Fiber optics is less susceptible to the outer interference than the metal cables. CCTV network, long distance switches, central offices, subscriber’s loop careers and industrial networks use fiber optics for communication purposes. In the near future, fiber optical cables will repalce the conventional coaxial and ethernet cables for the LAN networking.
Enterprise Optical Network.
Fiber optics also provides solutions for the enterprise networking like NAS (network attached storage) and SAN (storage area network). A NAS is a server that is used to data sharing in a network. NAS allows more hard disk storage space to be added to a network. A NAS device does not require to be attached to the server directly and it can be placed anywhere in the network. A NAS can be made up of two or more NAS and being a part of a network, the network user can access it from anywhere in the LAN. NAS is an efficient way of storage and file sharing. Fiber optics provide more efficiency and reliability in the NAS performance by providing more bandwidth and data capacity. SAN is a subnet of the shared storage devices in a LAN or a WAN. Fiber optics provide more high speed connectivity and speed among the SAN in a LAN or WAN.
Optical Network Devices
Fiber optic devices are in use in a number of ways like Networking, storage, industrial, medical, defense, broadcasting, telecommunication systems.Optical testers are designed for a variety of measurements and tests with a single meter.Attenuators are designed for single mode applications, multimode applications and for attenuation settings.Fiber Optic connectors are used to connect a fiber with another fiber or equipment. There are different types of connectors are being used today such as SMA, FC and SC connectors.
Optical Switch is a handheld device for calibration sets and measurements automation.
Optical Routers connects twisted pair LONWORK notes to the fiber optic backbones or subnets. They also re-routes the data automatically due to power failure of fiber break.
Major Optical Network Terms
Adaptor: It is a device for connecting two or connectors.
ADSL: Asymmetric Digital Subscriber lines is a most common form of the DSLAmplifier: It is a device that is used to amplify the signals without destroying the original wave shapes.
ATM: An abbreviation for the asynchronous transfer mode.
Attenuation: The reduction of the optical power as it passes through the fiber optic.
Attenuation: A device that is used to reduce the signal power in a fiber optic.
Backbone: Backbone is a high speed telecommunication network.
Bandwidth: The capacity of the medium.
Base band: A simplest method of the transmission in the LANS.
Biconic Connector: A type of the fiber optic connector.
Bit: An electrical pulse that carry signals.
Bandwidth: Capability of dealing with high speed, high capacity data transmission.
Cable: One or more fibers enclosed in the protecting covering.
CATV: An abbreviation of the community Antenna television of cable TV.
Coax: An abbreviation of the coaxial cable.
COMSAT: Communication satellite.
Coupler: A device that is used to distribute the power between two or more ports.
CWDM: Course wavelength division multiplexing.
Detector: Converts fiber signals into the electrical signals.
Duplex: The simultaneous operations of a circuit in both directions in a communication
network.
FDDN: Fiber data distribution network.
Fiber optic modems: Used for sending and receiving data.
Fiber Storage: High speed network technology used for storage.
MT Connector: Multi fiber connector used to hold 24 fibers.
ODS: Optical data storage.
PHY: Known as physical layer device.
POF: Plastic optical fiber.
Port: Connection point.
PTO: Public telecommunication operators.
RFI: Radio frequency interface.
SONET: Synchronous optical network.
TDM: Time division multiplexing.
Trunk: Circuit that connects two switching centers.
X Band: Frequency ranges between 8.0 to 8.4 G
What is Subnetting Mask?
Introduction to Subnetting?
Here you will find subnet network overview, ip addressing, address translation, network overview, subnet masking and subnetting overview. A subnet or a subnetwork is a separate part of an organization’s network. In a subnet all the machines are typically in one room, building or at one geographical location.
By dividing an organization’s network into the subnets allows it to connect to the internet by using the same shared network address. Without subnet’s an organization may get different connections to access the internet. Subnetting is the modification of a single IP network to create two or more logically different networks.
A subnet allows the flow of network traffic between hosts to be segregated based on the configuration of a network. Subnetting can improve the network security and performance by arranging the hosts into the different logical groups. Subnetting is required when one network address needs to be distributed across multiple network segments. Subnetting is required when a company uses two or more types of the network technologies like Ethernet and Token Ring.
Two network segments are restricted by distance limitations. Submetting or dividing the network into the segments is also required when localized network management is required for example accounting, sales, customer service departments. There is another reason for the subnetting, which is that the computers on the network, which use more bandwidth, needs to be separated from the rest of the computers. There are certain advantages and disadvantages of the subnetting. Before you start dividing your network into the different segments, you should assign the IP address to each computer in your network segment.
Subnetting makes the network management easier and it is also very helpful for the troubleshooting of a network segment. The internet is a collection of networks where users communication with each other. Each communication on the internet carries the source and the destination address of the computer. This address is called IP address. This 32 bit address has two parts: one part represents the network portion and the other part represents the host portion of the IP address. A company can use some of the bits in the machine or host portion of the address to identify a subnet. In this scenario, the IP address contains three parts: the network address, the subnet address and the machine address.
Subnet Mask Basics
The most recognizable part aspect of subnetting is the Subnet mask. A subnet mask contains 4 bytes, 32 bits and is divided into 4 period separated octets. Typically, a very common subnet mask in binary looks like this.
11111111 11111111 00000000 00000000
255 255 0 0
How to Apply a Subnet Mask
A subnet mask does not work like an IP address and it cannot exist separately without an IP address. An IP address and subnet mask work together to form a network. An IP address splits into two main parts when applying the subnet mask. The leftmost bits of a subnet mask must be set to 1. For example
11111111.00000000.00000000.00000000
11111111.11111111.00000000.00000000
11111111.11111111.11111111.00000000
The above example shows the valid representation of a subnet mask into the binary numbers.
00000000.00000000.00000000.00000000 is an invalid subnet mask. 11111111.11111111.11111111.11111111 is also invalid subnet mask.
All valid subnet masks contain two parts: the left side with all mask bits set to '1' (the extended network portion) and the right side with all bits set to '0' (the host portion), such as the first example above.
Subnetting an IP network can be performed for a variety of reasons such as using the different physical media in an organization, such as FDDI, WAN and Ethernet, preservation of the addresses and for the purpose of security, management and ease of troubleshooting. The most
common reason of the subnetting is to control the network traffic. In an Ethernet network, all computers in a segment see all the packets that are transmitted by all the other computers on the same segment.
In this situation, the network performance can be badly affected due to the heavy traffic loads, collisions and the retransmission of the packets. A router is used to connect the IP networks and it also helps to minimize the load of the traffic.
Subnet Masking
By applying the subnet mask to the IP address you can identify the network and host portion of the IP address. The decimal number 1 represents the network portion in the subnet mask and the node is represented the 0s. Performing a logical AND operation between the IP address and the subnet mask resulting in the network address. For example, using our test IP address and the default Class B subnet mask, we get:
10001100.10110011.11110000.11001000 140.179.240.200 IP address of the class B 11111111.11111111.00000000.00000000 255.255.000.000 Default subnet mask of class B
10001100.10110011.00000000.00000000 140.179.000.000 Network Address value
The following example shows the default subnet masks.
• Class A Subnet Mask- 255.0.0.0 - 11111111.00000000.00000000.00000000
• Class B Subnet Mask- 255.255.0.0 - 11111111.11111111.00000000.00000000
• Class C Subnet Mask- 255.255.255.0 - 11111111.11111111.11111111.00000000
Subnetting Review
Subnetting allows network and system administrators some flexibility in defining relationship among the hosts of a network. Hosts on the logically and physically different subnets can talk to each other through specialized devices called gateway or router. The ability to filter the traffic between
subnets can make the more bandwidth availability. Subnetting referred to as subdivision of a class based networks into subnetworks.
A router can exchange subnet routes with the other routers in the network. A subnetted network can’t be split into the isolated portion. All the subnets must be contiguous because the routing information cannot be passed to a non-network member. Router can exchange subnet routes with other routers within the network. Since the subnet masks are identical across the network, the routers will interpret these routes in the same manner. However, routers not attached to the subnetted network can't interpret these subnet routes, since they lack the subnet mask.
Therefore, subnet routes are not relayed to routers on other networks. This leads to our second
restriction. Subnetting allows you to create multiple logically different networks within the same class A, B or C. If you break a major network into smaller networks, it allows you to create a network of interconnecting subnetworks. Any device or gateway that is responsible for connecting the different subnetworks must have the distinct IP address one for each
subnetwork.
To subnet a network use and extend the natural subnet mask using some of the bits from the host ID portion to create a subnetwork ID. In this example, given a Class C network of the IP address 4.15.5.0 which has a natural subnet mask of 255.255.255.0, you can create subnets in this manner:
11001100.00001111.00000101.00000000 204.15.5.0
11111111.11111111.11111111.11100000 255.255.255.224
By extending the natural subnet mask to be 255.255.255.224, you have used three bits from the host portion of the mask and used them to make subnets. By using these 3 bits, it is possible to create 8 subnets. The remaining five ID bits of the host portion, each subnet can make 32 host addresses and the 30 addresses out of 32 are assigned to the devices or computers.
The host IDs of all zeros and all ones are not allowed.
204.15.5.0 255.255.255.224 host address range 1 to 30
204.15.5.32 255.255.255.224 host address range 33 to 62
204.15.5.64 255.255.255.224 host address range 65 to 94
204.15.5.96 255.255.255.224 host address range 97 to 126
204.15.5.128 255.255.255.224 host address range 129 to 158
204.15.5.160 255.255.255.224 host address range 161 to 190
204.15.5.192 255.255.255.224 host address range 193 to 222
204.15.5.224 255.255.255.224 host address range 225 to 254
IP Addressing
Introduction of IP Addressing
Here you will learn about ip address network introduction and general overview of routing, subnet mask, subnetting, data communication. IP address is an identifier for a computer or device on a TCP/IP network and Internet. Networks that use the TCP/IP protocols route traffic based on the IP address of the destination computer or network device. The format of the IP address is 32 bits 4 octets 4 bytes such as 100.100.10.1, 210.100.22.30, 1.10.1.2 these are the examples of the IP address. The format is a 32-bit numeric value written as four numbers and separated by periods.
Each number in the IP address can be between 0 and 255. In your private network, you can assign unique IP address randomly. However, when you want to connect your private network to the Public network such as Internet then you must need a registered IP address to communicate on the internet and to avoid duplicate address. The four numbers in an IP address are used in different ways to identify a particular network. The general internet registries such as APNIC, RIP, NCC and LACNIC assigns internet or IP addresses from the following 3 classes.
1. Class A- IP address from 0-126. It supports 16 million hosts and 126 networks.
2. Class B- IP address from 128-191. It supports 65,000 hosts and 16,000 networks.
3. Class C-IP address from 192-223. It supports 254 hosts and 2 million networks.The number
of unassigned IP address is running out and a new classless scheme called CIDR is replacing
the classes based system of the IP address. In this system the A, B and C class is tied to
adoption of IPV6.
Every device connected to the Internet must need a unique identifier, which is called an IP address. An IP address is a numeric value separated by periods into four octets. These numbers are usually assigned to the ISPs (internet service providers) within region-based blocks. An IP address can be used to identify a region or a country. An internet user’s geographical location can be determined with the help of an IP address. The number system is generally difficult to remember so the IP address may also assign to a Host name.
The host names are usually easy to remember. In simple words, every website on the internet must bound or mapped with an IP address. At one time ISPs usually issue one IP address to each user. Within each ISP a DHCP (Dynamic host configuration protocol) server is configured, which dynamically assigns IP addresses from a given pool to each user who connects to the ISP. Dynamic IP addresses also limit the ability of a user to host websites, mail servers, ftp server, mail server and web portals.
Understanding IP Addresses Scheme
An IP address is an address that is used to uniquely identify a device or computer on an IP-based network. An IP address is an address used to uniquely identify a device on an IP network. An IP address can be divided into two parts network portion and a host portion. Each IP address is associated with a subnet mask. The 32 bit address is broken into 4 octets and 1 octet=8 bits. Each octet is converted to a decimal and is separated by periods.
For example 0000000000.11111111.00000000.11111111 this is a binary representation of an IP address. Each octet’s decimal value ranges between 0 and 255. The binary octets convert into decimal value. Here you can see that how a binary octet converts into decimal value. The right most bit or least significant bit of an octet will hold a value of 20.The bit left to that bit will hold a value of 21. This process continues until the left most bit or the most significant bit holds the value of 27. If all the binary bits are one the decimal representation will be like this.
1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1 (128+64+32+16+8+4+2+1=255)
Now here is a sample conversion of the octet if not all the bits are set of 1.
0 0 1 0 0 0 0 1
0 0 32 0 0 0 0 1 (0+64+0+0+0+0+0+1=33)
In the following example you can see the IP address representation both in binary and decimal values.
64. 2. 135. 19 (decimal)64+2+135+19=220
01001010.00000010.1000111.00010011 (binary)
The octets are broken down to provide a large number of the addressing scheme that can accommodate small and very large networks. There are five different classes of the IP networks. Class A, B, C, D and E. The classes from A to C and mainly in use, D and E are experimental and reserved so they are not commonly in use. Due to the classless inter domain routing (CIDR) these addresses are not practically in use.
Network/Subnet Masks
A network mask helps you which portion of the address identifies the network portion and the host portion of an IP address. The three different classes of the IP addresses have their own default masks as shown below.
Class Subnet Mask
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0
An IP address on a class A network that has not been subnetted would have an address and subnet mask pair such as 10.111.20.1 255.0.0.0. If you want to know in more detail that how a mask help you identify the network and host part of the address simply convert the IP address and subnet mask into the binary numbers.
4.16.15.1= 00000100. 00010000.00001111.00000001
255.0.0.0 = 11111111. 00000000.00000000.00000000
If you have the address and the subnet mask in the binary forms then identifying the network portion and the host portion is very easy. Any address value that has the corresponding subnet mask binary value set to 1 show the network ID. Any address bit that has corresponding subnet mask value to 0 represents the host ID.
4.16.15.1= 00000100.00010000.00001111.00000001
255.0.0.0 = 11111111.00000000.00000000.00000000
Network id host id
If you know your IP address of a computer, you can access the services such as online games, FTP, Web and Mail servers, and remote access utilities such as Remotely Anywhere, PCToGo, PCAnywhere, Remote control etc. How do I change my IP address?There are a number of methods by which you can change the IP address of your computer.
What is a Proxy Server?
A proxy server is a computer that offers network and internet access services to the client computers in a network. A client computer connects to the proxy server, requests a connection, services, files and other resources on the other servers. In some cases, the proxy may alter the client’s request and the server’s response for various reasons. By using the proxy server you can hide, conceal and make your network id anonymous by hiding your IP address. To get the anonymous status on the network or Internet, strong intermediate methods are employed like cryptography etc. Examples are remailers, P2P systems etc.
There is a large number of the software available that allows you to hide your IP address with the help of the proxy servers. The well known software for this purpose is Hide IP, Stealth surf, Netconceal, Anonymous surfing, Proxify and Ghost surf.
An IP address is a unique identification number for communication between computer networks, network devices such as computers, fax machines, printers and servers. It is like the number of an apartment or a phone number. IP addresses are of two types Static and Dynamic. Internet service providers’ use dynamic IP addresses and servers usually use static IP address.The class A of the IP address constitutes almost 50% of all the IP addresses. This class is meant for large networks like the big multinational companies. Class B networks are medium sized like used in the colleges, Universities and other educational and training institutes. Class C IP addresses are usually used for the small companies.
The Regional Internet Registry (RIP) provides the IP addresses based on the geographical distribution. RIP also offers protection against the hackers that try to access the confidential data. All the personal information recorded by the ISP is kept in confidentiality.
Here you will learn about ip address network introduction and general overview of routing, subnet mask, subnetting, data communication. IP address is an identifier for a computer or device on a TCP/IP network and Internet. Networks that use the TCP/IP protocols route traffic based on the IP address of the destination computer or network device. The format of the IP address is 32 bits 4 octets 4 bytes such as 100.100.10.1, 210.100.22.30, 1.10.1.2 these are the examples of the IP address. The format is a 32-bit numeric value written as four numbers and separated by periods.
Each number in the IP address can be between 0 and 255. In your private network, you can assign unique IP address randomly. However, when you want to connect your private network to the Public network such as Internet then you must need a registered IP address to communicate on the internet and to avoid duplicate address. The four numbers in an IP address are used in different ways to identify a particular network. The general internet registries such as APNIC, RIP, NCC and LACNIC assigns internet or IP addresses from the following 3 classes.
1. Class A- IP address from 0-126. It supports 16 million hosts and 126 networks.
2. Class B- IP address from 128-191. It supports 65,000 hosts and 16,000 networks.
3. Class C-IP address from 192-223. It supports 254 hosts and 2 million networks.The number
of unassigned IP address is running out and a new classless scheme called CIDR is replacing
the classes based system of the IP address. In this system the A, B and C class is tied to
adoption of IPV6.
Every device connected to the Internet must need a unique identifier, which is called an IP address. An IP address is a numeric value separated by periods into four octets. These numbers are usually assigned to the ISPs (internet service providers) within region-based blocks. An IP address can be used to identify a region or a country. An internet user’s geographical location can be determined with the help of an IP address. The number system is generally difficult to remember so the IP address may also assign to a Host name.
The host names are usually easy to remember. In simple words, every website on the internet must bound or mapped with an IP address. At one time ISPs usually issue one IP address to each user. Within each ISP a DHCP (Dynamic host configuration protocol) server is configured, which dynamically assigns IP addresses from a given pool to each user who connects to the ISP. Dynamic IP addresses also limit the ability of a user to host websites, mail servers, ftp server, mail server and web portals.
Understanding IP Addresses Scheme
An IP address is an address that is used to uniquely identify a device or computer on an IP-based network. An IP address is an address used to uniquely identify a device on an IP network. An IP address can be divided into two parts network portion and a host portion. Each IP address is associated with a subnet mask. The 32 bit address is broken into 4 octets and 1 octet=8 bits. Each octet is converted to a decimal and is separated by periods.
For example 0000000000.11111111.00000000.11111111 this is a binary representation of an IP address. Each octet’s decimal value ranges between 0 and 255. The binary octets convert into decimal value. Here you can see that how a binary octet converts into decimal value. The right most bit or least significant bit of an octet will hold a value of 20.The bit left to that bit will hold a value of 21. This process continues until the left most bit or the most significant bit holds the value of 27. If all the binary bits are one the decimal representation will be like this.
1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1 (128+64+32+16+8+4+2+1=255)
Now here is a sample conversion of the octet if not all the bits are set of 1.
0 0 1 0 0 0 0 1
0 0 32 0 0 0 0 1 (0+64+0+0+0+0+0+1=33)
In the following example you can see the IP address representation both in binary and decimal values.
64. 2. 135. 19 (decimal)64+2+135+19=220
01001010.00000010.1000111.00010011 (binary)
The octets are broken down to provide a large number of the addressing scheme that can accommodate small and very large networks. There are five different classes of the IP networks. Class A, B, C, D and E. The classes from A to C and mainly in use, D and E are experimental and reserved so they are not commonly in use. Due to the classless inter domain routing (CIDR) these addresses are not practically in use.
Network/Subnet Masks
A network mask helps you which portion of the address identifies the network portion and the host portion of an IP address. The three different classes of the IP addresses have their own default masks as shown below.
Class Subnet Mask
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0
An IP address on a class A network that has not been subnetted would have an address and subnet mask pair such as 10.111.20.1 255.0.0.0. If you want to know in more detail that how a mask help you identify the network and host part of the address simply convert the IP address and subnet mask into the binary numbers.
4.16.15.1= 00000100. 00010000.00001111.00000001
255.0.0.0 = 11111111. 00000000.00000000.00000000
If you have the address and the subnet mask in the binary forms then identifying the network portion and the host portion is very easy. Any address value that has the corresponding subnet mask binary value set to 1 show the network ID. Any address bit that has corresponding subnet mask value to 0 represents the host ID.
4.16.15.1= 00000100.00010000.00001111.00000001
255.0.0.0 = 11111111.00000000.00000000.00000000
Network id host id
If you know your IP address of a computer, you can access the services such as online games, FTP, Web and Mail servers, and remote access utilities such as Remotely Anywhere, PCToGo, PCAnywhere, Remote control etc. How do I change my IP address?There are a number of methods by which you can change the IP address of your computer.
What is a Proxy Server?
A proxy server is a computer that offers network and internet access services to the client computers in a network. A client computer connects to the proxy server, requests a connection, services, files and other resources on the other servers. In some cases, the proxy may alter the client’s request and the server’s response for various reasons. By using the proxy server you can hide, conceal and make your network id anonymous by hiding your IP address. To get the anonymous status on the network or Internet, strong intermediate methods are employed like cryptography etc. Examples are remailers, P2P systems etc.
There is a large number of the software available that allows you to hide your IP address with the help of the proxy servers. The well known software for this purpose is Hide IP, Stealth surf, Netconceal, Anonymous surfing, Proxify and Ghost surf.
An IP address is a unique identification number for communication between computer networks, network devices such as computers, fax machines, printers and servers. It is like the number of an apartment or a phone number. IP addresses are of two types Static and Dynamic. Internet service providers’ use dynamic IP addresses and servers usually use static IP address.The class A of the IP address constitutes almost 50% of all the IP addresses. This class is meant for large networks like the big multinational companies. Class B networks are medium sized like used in the colleges, Universities and other educational and training institutes. Class C IP addresses are usually used for the small companies.
The Regional Internet Registry (RIP) provides the IP addresses based on the geographical distribution. RIP also offers protection against the hackers that try to access the confidential data. All the personal information recorded by the ISP is kept in confidentiality.
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