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admin on Tuesday, March 9th, 2010 |
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A computer network is a collection of two or more computers with communication between them through a medium. The communication medium can be through radio waves, wires, infrared, optical fibers etc.
Computer network is an integral part of our daily lives, with the most important reason being that of communication. The use of computer networking is to share resources like fax machines, printers, modems, files etc., and its other uses are database server, computer server, email, chat, internet etc. The computer to which the resources are attached is called the server and the other computers that access the resource are called clients. In peer-to-peer computer networks there are no servers.
The sharing of fax machines, printers, and modems amongst many computers and users reduce the operational cost. A database on a computer network is a very important application as it stores and runs many important data and jobs. Emails and chats can be used for instantaneous communication and sending of files on a computer network.
The computer networks are classified, depending upon the size, as Local Area Networks (LAN), Wide Area Networks (WAN), Metropolitan Area Networks (MAN) and Personal Area Networks (PAN). The topology (topology is the way the computer networks and network resources are connected) of the networking can be classified as Bus Network, Ring Network and Star Network.
The networking hardware basically consists of wiring, network cards and a hub. Computer network cards are required so that one computer can understand what the other computer is “talking”. Network… Read the rest
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admin on Wednesday, January 13th, 2010 |
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Cabling of data and voice systems is often ignored by many companies until the last minute just before relocation or new building takes place. Many information systems professionals view it as a low priority or something that just takes away from their budget for real network components such as servers or software. However having a state of the art easy to manage cabling system is just as important as good reliable servers on a network. Cabling is the backbone of any computer network; it ties all the components of the network together therefore it should receive as much careful consideration as any other network component.
Mistake number one ? Blindly choosing the lowest bidder
This is the most common mistake made when installing voice and data network cabling. Often the lowest bidder is the contractor who is the smallest, has the least experience or the one that made a mistake on their bid. Prior to making this decision you should know your contractor. Find out how long they have been in business, visit some of the large installations they have done and by all means go visit their offices and warehouse. A site visit to their office will tell you most of what you need to know about an organization. Make sure your contractor has completed jobs of similar scope and size.
Mistake number two ? Choosing the manufactures product that will be installed
Many companies have tried to standardize on a particular manufacture of cabling system. Some of the… Read the rest
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admin on Wednesday, December 9th, 2009 |
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There are more and more individuals opting to work from home than ever before. The advantages to this are many including avoiding the morning and evening rush hours, being able to spend time with your kids and significant other, and doing everything on your own time. Though the pitfalls are many, the one that I will be focusing on in this article is that of setting up a secure wireless network for your home based business. Right now somewhere out there, there is someone with a receiver waiting to pick up on an unsuspecting person’s wireless local area network. Their hope is to garner some sensitive information that may lead to identity theft, and stolen proprietary business information.
Most businesses owners are not technically inclined, though they may be power users, in general security settings is not one of the first things they want to mess around with in their day to day operations. This makes most wireless LANs a great target for information predators.
Here are some general guidelines to follow in setting up your wireless network. Though it may vary from vendor to vendor, the gist is more or less the same:
1. Setup the wireless access/router point via a wired client.
2. Always change the factory setting password to something difficult for someone to guess.
3. Enable 128-bit Wired Equivalency Privacy (WEP) encryption on both your access point and network card. From time to time change the WEP key entries. If your hardware does… Read the rest
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admin on Saturday, October 10th, 2009 |
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People have more flexible time due to wireless network. Thanks to the invention of wireless. People can now work from home while taking care of their kids or doing house works. No more stress from traffic jam anymore. Is this great?
Well, there is something you should realize. Working from home while using a wireless local area network (WLAN) may lead to theft of sensitive information and hacker or virus infiltration unless proper measures are taken. As WLANs send information over radio waves, someone with a receiver in your area could be picking up the transmission, thus gaining access to your computer. They could load viruses on to your laptop which could be transferred to the company’s network when you go back to work.
Believe it or not! Up to 75 per cent of WLAN users do not have standard security features installed, while 20 per cent are left completely open as default configurations are not secured, but made for the users to have their network up and running ASAP. It is recommended that wireless router/access point setup be always done though a wired client.
You can setup your security by follow these steps:
1. Change default administrative password on wireless router/access point to a secured password.
2. Enable at least 128-bit WEP encryption on both card and access point. Change your WEP keys periodically. If equipment does not support at least 128-bit WEP encryption, consider replacing it. Although there are security issues with WEP, it represents minimum… Read the rest
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admin on Thursday, September 10th, 2009 |
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The Answer To The Media Access Control Question
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Over the past few weeks I have received quite a few e-mails about Ethernet cards, both wired and wireless, and more specifically, about Media Access Control (MAC) addresses. I think the main reason I’ve received so many questions about Ethernet cards and MAC addresses is people trying to secure their home wireless networks and their desire to use MAC address filtering. This type of filtering in wireless networks can be configured to allow or deny specific computers to use or attach to the wireless network, based on the MAC address.
My first thought was to write an article just about MAC addresses and wireless Ethernet. After thinking about it I decided to expand on this and go over some specific information about Ethernet cards and communication.
Different Ways Of Finding Your MAC Address And More
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There are several ways of finding your Ethernet and communications protocol information. Many Ethernet card manufacturer’s have proprietary software that can reveal this information but they work differently depending on the manufacturer. So we will use the Windows 2000 and XP “ipconfig” utility since this is available in the majority of Windows Operating Systems.
First, go to “start” -> “run” and type “cmd” without the quotes. Then hit the enter key. At the command line type “ipconfig /all”, again without the quotes. Actually, just typing ipconfig without the /all will work but will only provide you with abbreviated information regarding your… Read the rest
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admin on Sunday, May 17th, 2009 |
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1. Network interface(Data link) layer
2. Network layer
3. Transport layer
4. Application layer
Network interface layer
The lowest layer of the TCP/IP model. Its task is to provide access to the transmission physical medium and it differs according to the implementation of the medium.
Network layer
The network layer provides network addressing, routing and datagram transmission. Used protocols that will be of interest further regarding DHCP are IP and ARP.
IP protocol
It is the basic protocol of the network layer and in general the internet as a whole. It sends datagrams, which are independent units that contain information about the destination, source and the sequence number of the datagram. The sequence number is used for message reconstruction, since the delivery order of the datagrams might not be the same as their order in the message and delivery reliability isn’t guaranteed at all.
IP protocol versions:
” IP v4 – 32 bit addresses. Provides approximately 4 billion unique addresses which aren’t sufficient at present times.
” IP v6 – 128 bit addresses. The transition to v6 will bring (is bringing) higher security, QoS, packet segmentation and many more IP addresses. (the transition from IP v4 to IP v6 must be supported by the system provider)
ARP protocol
The ARP abbreviation stands for Address Resolution Protocol. This protocol is used to find the physical address (MAC) based on a known IP address. If required ARP sends information… Read the rest