I have 2 windows xp (professional, sp3 all patched up, IE8 on a 2003 AD domain) that the firewall logs show a couple of attempts to connect on port 500 udp to every website the browser visits. The only problem I see this causes is that it slows the initial loading of a page down. If I stop IPSEC Services, the problem stops. I have run several types of avscans and compared config to several machines that do not have the problem and I can find nothing unusual. These machines are always on the inside and there are no vpn's in use.
I know this must be obvious, but I sure can't see it. Any help would be appreciated.