I am having a very strange problem with the network stack on my main WinXP machine. The problem is very (ok, very, very) vaguely empeg related

Every couple of days the machine will fail to be able to talk to certain websites. One of the websites is empegbbs.com , hence the tenious empeg connection.

When this happens none of the browsers on the machine will be able to reach the effected sites. I have tried with both IE and Firefox, the problem is the same on both.

It looks like a problem at the TCP level as the browsers just take a long time to timeout. However if I telnet to port 80 on empegbbs.com and request the root of its default website I get the data I expect (not the empegbbs site as I didn't bother to send the correct host header). That would suggest it is not at the TCP level.

I can fix the problem by disabling and re-enabling the Ethernet interface on my machine.

The only think I can think of is some odd MTU discovery problem, but other than that I am stumped. I guess I really need to do some sniffing when it happens next.

Anyone seen anything like this before ?

You got any antivirus scanners which intercept HTTP traffic or any proxies for that matter?

I was getting odd errors like "Unable to access document '/'" from Firefox for certain sites until I worked out it was the Internet monitoring part of NOD32. Disabled it and it's been working fine since.

No, nothing like that. The only AV I am running is AVG, which doesn't mess with network connections.

It just happened again, for the second time today. This time I did some sniffing.

Using Ethereal I could see that neither IE or Firefox were even managing to send a TCP SYN request. There was no data being sent at all.

At the same time I could telnet to port 80 on www.empegbbs.com just fine and that showed up in the Ethereal trace.

So it would look like there is a problem at the WinHTTP level, but I would be surprised to find that Firefox used that ? I would have imagined that it did all its own HTTP handling and didn't rely on the Windows WinHTTP code.

Spyware, dataminers

I would run spybot search and destroy and post here which if any it finds, I have seen VB spyware cause that type of issue also make sure you don't have a redirector in your lmhosts or hosts file.

Is your "BT" router running ok ???

This sounds familiar, I have had a couple of customers complain about a similar problem, but they have to reboot the router to get it connected again, and more often than not the blue connection screen would show Idle.

I have to admit I have never tried Telnet or FTP on a router when a customer has reported this, I will make a mental note to do so in the future.

This is course if this is going via ADSL ???

Edit - Just re-read your last post, my suggestion seems unlikley

Cheers

Cris.

AVG, Ad-Aware and Spybot all give me a clean bill of health (apart from the normal selection of tracking cookies).

Have you tried following this?

http://support.microsoft.com/kb/299357/

Or maybe this'll help

http://support.microsoft.com/kb/811259/

And I've just discovered a very intersting page that has lots of info on windows networking problem solving.

http://www.michna.com/kb/wxnet.htm

Hope this helps!