Very, very, very weird connection problem

This is the situation:

  • running phpBB, Wordpress, SVN, some other, all successfully for months, some for years
  • suddenly unable to upload media via the applications (attachments in phpBB, media in Wordpress, etc)
  • WebFTP gives me connection problems too
  • normal FTP too: able to create directories, but unable to put files

What seems to be the matter: it is my pc that is somehow not willing to do HTTP POST to dreamhost ?! I can upload to any other site, but not dreamhost. Even more weird: from within a VM on that same pc it does work, from another pc on the same lan it works too… so it is not my router or a network thing. The pc runs XP sp2. I have already run “winsockxpfix”, registry cleaners, etc, to no avail.

Sniffing the packets I see one HTTP Post packet and then the conversations stops.

I can still browse everything just fine, only sending data to dreamhost gets blocked somewhere.

I have absolutely no idea how to fix this or even where to look. I am hoping some genius here can give me a clue!

(I had to post this from within a VM!)

XP sp2
D-Link 655 router
no firewall
no antivirus (for now)