HTTP access broken in Windows XP

[ergosteur]

Hi, not sure if this is the right forum to ask this in, but it's one of the few communities i'm a member of.

 

My problem is that when I start up winxp, everything is fine. But if i don't use my browser for a while, Windows stops letting me access HTTP sites. FTP and HTTPS and samba/windows shares work fine, even Google talk, skype and Windows Live stay signed in. I just can't get access to any unencrypted web sites. I've gotten around the problem by using Tor+vidalia, but it's just too slow.

 

I know that this is not due to my internet connection/router/wireless card. I have the same problem on my university campus, at residence, and at home. I've tried swapping the MiniPCI-E card, and used a PCMCIA adapter, and the Wired ethernet.

 

Note that I have no firewall. Also, I have Cisco VPN Client and VMWare installed, both of which create virtual network adapters.

Anyone ever had this problem/found a solution?

[ergosteur]

ok, so i resorted to the be-all end-all fix for any OS: format, reinstall.

 

still, it was a really odd problem, so if anyone has any idea what might have caused it....

[Metrogirl]

Sorry I missed this one when you first posted it, I was away. Yes, this is certainly the right place to ask questions like this. For HTTP to stop working, something is interfering with port 80. As HTTPS worked, this is fairly conclusive; other port connections were getting through.

 

There could be several possibilities. First off I'd have checked the proxy settings in IE. If something reconfigured the HTTP proxy settings (VPNs can do this silently) and didn't restore them, for example after a system crash with the VPN active, that could completely stuff your connection. Then I'd have checked the Windows Firewall and Internet Sharing services and killed them off. I'd also try loading a clean copy of another browser to see if it's an IE problem (at the same time avoiding any plugins, ActiveX that might have been dumped into IE's stack). There are tools that send and receive raw HTTP which sidestep IE altogether (like SamSpade); by elimination you could find out if it's the browser, something blocking port 80 at system level or a more generic IP stack issue. And of course some virus/trojan/malware can introduce nasties into the stack which can have very strange results.

 

Anyway, it's academic now, but with all these things the secret is to narrow down the problem by eliminating each component in turn. And when you've ruled out something, restore its settings to how they were, or you may introduce another problem. My guess is that the proxy settings in IE were screwed somehow and HTTP wasn't going out on port 80 directly to the sites you wanted.