Problem for connecting my computer to my wireless router via ethernet cable

Question

I have a wireles router model BEFW11S4. I have three computers connected to the router by wireless. All these connection work well. I have also a computer connected to the same router via an ethernet cable. This connection does not work, I cannot access internet with that computer. What can I do to correct the problem?

Answer 1

First off, you need to ascertain if the network card in the computer that is not working is capable of sending and receiving legitimate packets.
Best thing to do is try and connect this machine directly to your Internet Service Provider modem and see if it works.
If it doesn't, first you need to check if your computer is capable of acquiring an IP address automatically (See below for details).
If it is setup to acquire an IP address automatically, but still does not work you either need to find someone who knows how to test network hardware for you or you could try installing a different network card in your computer.
There are 2 ways a computer can receive an IP address. A typical way is for your router to provide one to the workstation using something called DHCP. The other method requires you to know the exact IP addressing required on your LAN such that your workstation when manually configured with an IP address knows where to send it's packets to get out to the Internet.
To check if the computer that does not work is configured to "automatically" receive an IP address from your router, do the following:
1. click on Start
2. click on Control Panel
3. double-click on Network Connections
4. right single-click on "Local Area Connection"
5. click on Properties
6. Scroll down the list until you see "Internet Protocol (TCPIP)"
and then double-click that item
7. Make sure "Obtain an IP address automatically" and "Obtain DNS server address automatically" are checked.
This setting allows the workstation to send a broadcast message looking for a DHCP server which can assign an IP address to the workstation. Your router typically would have a DHCP server configured for providing IP addresses. The typical home-based routers can be configured to run a DHCP server or not. Chances are that your wireless computers are automatically acquiring an IP address from your router and therefore it should work on Ethernet connections as well.
It is possible for something to be not working inside your router that would prevent the DHCP server from distributing IP addresses only on the Ethernet connections. If this is the case you would have to acquire a new router.
There is more that can be looked at, but this is where you need to start.