[Big Mac]

About three weeks ago I began experiencing a mysterious, intermittent network connectivity problem that I don't really understand. The problem was experienced on my Core i7 PC running Windows 7 x64. It began with a loss of network connectivity coming out of sleep mode. My PC is connected directly to my U-verse router by Ethernet. Using ipconfig /renew would usually get the connection restored at first, but then it started happening more frequently and the command would only restore the connection for a few seconds before it went down again. At the height of this problem I was issuing multiple ipconfig commands and the network just wouldn't stay up. I would have no Internet on my powerful PC for a day.

Two strange factors: 1) WIFI from my router would continue to work without any issue during these problems; 2) the problem went away over the last few days just as it came in. I started being able to restore the connection for long periods after two or three ipconfig commands, and then after that the connection would persist until coming out of sleep. Now today I woke up my PC and got a connection out of sleep for the first time in weeks.

Any clue as to the problem here? I'm concerned that since I don't know the cause it may recur and I won't have a way to cure it.

Things I tried that didn't seem to work:

1. Restarting the router (did that a couple of times, both software and hardware restarts);

2. Added Google's DNS to my primary DNS setting in Windows.

[ghporter]

Try a different Ethernet port on the router. Try a different cable. If these don't help, try a "known good" cable between the PC's Ethernet port and another computer's-try to set up a direct connection between the two to test the PC's Ethernet port. Also try wiring any of the wireless computers to the router and use this connection to check the wired ports.

Since you never had WiFi problems, the router and modem are obviously working, even if the wired router is giving you problems. Just about the only thing left are the wired connection

[Big Mac]

Thank you very much for your analysis of the problem, Glenn. I was thinking along the same lines, although I kind of discounted that it could be the cable at fault and thought my built-in Ethernet support on my Gigabyte motherboard was to blame. I will try a different cable since I just conveniently found where I placed a bag of extra cables. . .

Thank you for the very quick response, btw.

Update: Now this is really odd. I just found that my WIFI is now down while my wired connection is working fine!

[seanc]

It's sounding more like you have a faulty router.
Any firmware updates available?

On the coincidental side, I had a G41M based Gigabyte board with an on-board network card fail this week.
Plugging the network card in while Windows was running would cause the PC to hard lock, PXE booting from the network was hit and miss.
Replaced the board and everything is fine.

[ghporter]

I agree with seanc that your router seems dodgy. Have you HARD booted it? Have you COLD booted it? To hard boot, you unplug power and wait about a minute, then plug it back in. To cold boot, you unplug power and wait a lot longer-I'd recommend at least 10 minutes or more. Both "reinitialize" the microcomputer that runs your router, but there are a lot of such devices that manage to hold their RAM a lot longer than you'd expect. If that doesn't give you a decently functioning router, try finding at least the current version of the router's firmware and loading that. These little micro boxes tend to be a little flaky after a while...

You didn't mention what router you have. Apparently it's a 2-Wire box, but which one? And as seanc points out, those Gigabyte (and other brands) boards with everything on the board can be a hassle if something that's integrated gets fouled up. Fortunately, Gigabyte boards are reasonably priced, so if it turns out to be that, it's not going to break the bank to replace the board.

[seanc]

I might also add that Gigabyte boards have very good warranty periods - they range from 3 to 5 years depending on which board you buy and the RMA service (at least in the UK) is excellent.
My opinion of the RMA service should not be taken as an indicator that the boards are flakey, I just have hundreds of machines running with them, there's always the odd few that stop working.

[ghporter]

Gigabyte has good customer service, and they like to support customers to keep them as customers. Good boards...

[Big Mac]

It's a 2WIRE 637, and I guess the WIFI wonkiness is a confirmation that it's going bad. AT&T locks these routers down with their own proprietary interfaces pretty well, so I'm not even sure if I have any firmware update access.

Regarding the motherboard replacement discussion, after the difficulty I experienced getting a third party heat sink installed I'm really hoping I don't ever have to do that. I think I'd rather build a whole new PC than swap out a motherboard in my existing one. But it's good to know you guys have had positive experiences with Gigabyte regarding replacement service.

[seanc]

637? Never heard of that model.
Did you get the 637 from your wireless network SSID? If so, that's not the model.
The model will be on a sticker on the unit.

[Big Mac]

Oh yeah, that's what the SSID was set to so that's what I assumed the model was. It's less than a year old. I guess I'll call and complain to AT&T.

[Cold Warrior]

It's probably the serial number (part of it) being used to form the SSID (reference).

[ghporter]

On the plus side, 2Wire at least gives their routers (relatively) unique default SSIDs. On the minus side, AT&T wants you to think that they're locked. They're not, really. AT&T doesn't want a bunch of users to goober up their devices and thus generate tons of support calls, so they use a feature of the boxes' configuration system to make that very hard. But it only takes a little searching to find resources like 2Wire themselves, BroadbandReports, and even eHow...

But take advantage of the fact that AT&T supports that device, and have 'em come out and replace it.