Ethernet not working

I have a 2010 MBP with 8 GB of RAM running OS X Lion.

I am at college and our wifi is slow, but they have an ethernet port. So I bought a cable and plugged it in. I turned off the wifi, and under system preferences, it says the ethernet port is connected and is giving me an IP address. Yet the internet wont work. Is there any reason for this? A couple other Mac users here have the same issue. But there is a kid with a PC and it's working fine for him. Any insight into this? I really could use some decent internet.

Anyone? I can't seem to find anything terribly helpful on google.

Ok, what IP address is showing under Ethernet? Do you have DHCP enabled?

The IP address is :

169.254.173.105

The DHCP is enabled.

Any ip address that starts with a 169 tells you that your computer is not connecting to anything, to put it in simple terms.

I was aware of that. I am just confused as to why it is not connecting. It says it is connecting.

Are the Windows machines set for DHCP that are connecting? That is a strange one.

I am not entirely sure on that one. I will definitely check on that today. My brother has a mac and last year he connected through ethernet here. So I am very confused. So are the rest of the mac users. I thought possibly it's a strange incompatibility with Lion, but I don't think everyone here has upgraded.

what is your lion 10.7.1 or 10.7 ? run software update if it is 10.7, might get your right.

Lion is updated. My friend is using DHCP on Linux. He doesn't know why the internet won't work for me either.

If you reboot to either the recovery partition of Lion, or from the Snow Leopard disk that came with your computer, there are hardware tests (at least I believe this is the case in Lion.. since I don't use it). Boot off of this, and see if the ethernet port is working. If it is, this verifies the hardware is OK, so we're looking at a configuration issue. I've seen this before, and had to delete the network preferences to resolve it.

If you're in a college environment, you most likely will have to register your network device with the IT department. Most colleges have security software in place, sort of like the guy with a clipboard in front of a nightclub. If you aren't on the list, you aren't getting in. The IT department will register your computer as an approved device, they might provide some network settings you have to enter on your computer, and then you should be able to hop online. Keep in mind, there's a good chance that questionable activity will be monitored.

I'm going to take Leroy down to the IT department and see what's up. Thanks for all of the help guys!

-BTW, the reason I didn't take it down in the beginning is because I'm afraid they will take Leroy away. Other people have had issues with long wait times. Hopefully they can resolve the issue while i am there.

I got it. For some reason Leroy thought there were 2 ethernet ports and it was screwing up the connection process.