wingate 6.1 checksum failure

[oyvindroset@hotmail.com]

Hi.
I have got a strange situation with my wingate setup, and would really like to know what to do next.
I have a laptop, with two NICs. One wireless to the internet and one ethernet connected to the firewall (dedicated server) From this laptop, internet access is ok, no problem.
I am using NAT, not proxy.
The problem is: When clients from the internal network tries to surf the net, the wingate server drops the traffic with the "checksum failure" message. (Flags = AP)
But pinging the same web server works fine!
Telnet towards the web server is also fine, I do get to connect on port 80 and I do get some html back.
But when using Internet Explorer, it first says "connecting to www.vg.no" and then "web site found" but after that, nothing. I have been sniffing the traffic from the internal client and it sends out the syn packets, but no answer is coming back.
I have configured the wireless Nic as external and the ethernet nic as internal on the wingate server.
In the activity window on the wingate server, everything seems fine, showing the NAT connections from the client, towards the web server.

[takusa100]

Excuse me , and i wanna know where you see the "checksum failure" messages and "Flags AP"?
i think maybe you can setup a logfile on the wingate server .test whether the data which from client to the server is fine.

[oyvindroset@hotmail.com]

Thanks for you reply, takusa100! :-)
But:
I solved the problem just now!

I would just like to tell you that this problem no longer exist.
After trying different things for a long time, I finally tried to run RDP against the wingate server, from a client. And then the firewall log said the same thing, checksum failed.
And I started thinking, what if there is something wrong with the ethernet NIC? I switched to a different laptop, installed wingate, same setup as the previous one and Voila! Everything works great!
So this old laptop ethernet card somehow managed to destroy the validity of the packets, making the wingate fw dropping them.

Thanks,