Is my mobo's ethernet port bad?

[E-66]

I've had a Gigabyte GA-P35-DS3L motherboard for several months that I was planning on building a system around but just haven't yet. I've installed XP quite a few times but haven't activated it yet. Up until now I've had no issues. Yesterday I installed XP again and I couldn't get online. The network icon on the taskbar shows a little red blip moving between the two computers, and when you hover the cursor over it it says it's trying to acquire a network address, which it fails to do. It then shows a yellow exclamation point over it and says "This connection has limited or no connectivity." I clicked on the 'repair' option, and that fails because it says it can't renew the IP address.

I downloaded a diagnostic program from the Realtek site, but it didn't didn't find any issues, nor are any problems showing up in Device Manager, and I know it's not the cable.

Where do I go from here?  Thanks.

[Redhatcc]

i would probally restart the router... sounds more to me like the computer and ethernet port is working but the router isnt giving you a good connection.

also i would go in cmd and type

ipconfig /release (press enter)

then

ipconfig /renew (press enter)

but im by far no network or internet specialist lol thats just what i would try first..

[E-66]

Thanks for the reply. I don't have a router, the PC is connected directly to a cable modem. The ipconfig /renew command didn't work. I can see what the problem is, I just don't know what to do to fix it. It can't connect to the DHCP server, it just sits there until it times out. Here's a ipconfig /all copy & paste. Apparently the 169.254.x.x IP address is an internal Windows address that means the connection isn't working. Great, but what's my next step?

C:\>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : test-44349101

Primary Dns Suffix . . . . . . . :

Node Type . . . . . . . . . . . . : Unknown

IP Routing Enabled. . . . . . . . : No

WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :

Description . . . . . . . . . . . : Realtek RTL8168/8111 PCI-E Gigabit Ethernet NIC

Physical Address. . . . . . . . . : 00-1D-7D-E5-B9-D9

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : Yes

Autoconfiguration IP Address. . . : 169.254.252.106

Subnet Mask . . . . . . . . . . . : 255.255.0.0

Default Gateway . . . . . . . . . :

C:\>ipconfig /release

Windows IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :

IP Address. . . . . . . . . . . . : 0.0.0.0

Subnet Mask . . . . . . . . . . . : 0.0.0.0

Default Gateway . . . . . . . . . :

C:\>ipconfig /renew

Windows IP Configuration

An error occurred while renewing interface Local Area Connection : unable to contact your DHCP server. Request has timed out.

[Ponch]

Can you not test it with an other PC, a cross cable and fixed IPs ?

Are you sure you installed XP the same way as the previous times and no settings modification ?

Can you have your ISP (if that's what's on the other end) doing some basic checks ?

[E-66]

Problem solved. It wasn't the ethernet port, it had something to do with communication between the port and the cable modem. Following a suggestion I got, I did a loopback ping to verify that the port was ok. Then I read through the troubleshooting issues in the cable modem's manual. It looked like I was going to have to call my ISP, but then I saw where it said to reset the modem before calling. I did that, waited a couple minutes, and everything was fine.

Something I'm curious about (since I know very little about network related things).... what happened that required me to have to reset the modem? The modem worked fine with the fully functional PC I had it hooked up to all along, but not with the PC I was having the issue with. Then after I reset the modem it worked fine with that PC, but not the original one, so I reset it again and then it worked with the original one again. Also, I have a NIC card in the first PC. One of the first things I did when trying to fix the problem myself was to put it in the second PC. When I did that I wasn't surprised that I had a successful connection (without resetting the modem), yet with the built-in ethernet port I had nothing until last night when I reset the modem.

Network stuff is a mystery to me, it's an area I've never learned much about. If anyone wants to offer an explanation I'd be glad to hear it. If not then I'll just be happy that I have a good connection again.

[Ponch]

Your explanation is a bit complicated (sorry, I read it 3 times and can't get it clear ).

A few ideas:

-some ISP want you to hook only one computer so they lock the MAC adress to be used. Using an other MAC adress requires rebooting the modem or ringing the ISP.

-you have 2 network cards in one of your PC (not clear which one), your "IPconfigs" infos show only one adapter. Maybe a driver or configuration problem (both DHCP ?) or IP adress conflict. I don't know if you can have 2 network cards with the same IP in a computer, I never tried.

[James_A]

The first point sounds like what is happening here. It seems this ISP does not want to hand out IP addresses, unless the modem is first rebooted/reset, since there was apparantly no response to the ipconfig /renew command.

Strictly speaking an APIPA address (169.254.x.x address) means only that there is no DHCP server response. It tells you nothing about whether the adapter or connection is working or not working.

If resetting the modem reliably gives a new connection, that suggests that everything else is actually working OK.

[Tripredacus]

I have the answer you are looking for. Having formerly worked in the cable internet business helps me here!

Almost all cable modems (that do not have built-in routers) learn the MAC address of the device (your computer) that is connected to it. So your modem registered the MAC Address of your first computer, and will only do business with a computer with that address. In order for it to recognize a different device/interface/comptuer, you need to unpower the modem and power it back on.

If you have access to the internal page of the modem (as long as your ISP hasn't blocked it out) you will find where this information is kept.

I'm not entirely sure why modems do this but they all do it. It must be something buried in a standard someplace.