[strongSwan] iPhone 3G connects fine, but Windows 7 doesn't!

[Deniz Acay]

Hi everybody,

I have a weird problem and none of the advices I found on the internet 
fixed this issue. Looks like Windows 7 interoperability page is old, so 
I am guessing that it may be related to Windows 7.

I have a Debian 6.0 server on Rackspace CloudServers and I am using the 
latest version of strongSwan (compiled from source with radius, 
nat-transport support, etc.).

I tried both machine certificates and EAP-MSCHAPv2 to authenticate to 
the server. Everything looks fine from the server's log, but the Windows 
7 machine hangs on the "Verifying username and password..." screen and 
mysteriously fails with a message with error code 809 indicating that 
the server is not responding... I have used tcpdump on the server and 
WinDump on Windows machine; negotiation on server is OK but if every 
setting is correct Windows machine does not get any response.

I am using iPhone 3G with exact same WiFi and router, but it connects 
fine. If this is a problem with my router or ISP, wouldn't I encounter 
the same problem with iPhone?

I'll appreciate any help...

Regards,
Deniz