Hi,
First , to the most extent, I can confirm it is DNS problem, because:
1. If dns is Ok, ping forums.qbik.com should get IP Address at least, should not get unknow host(pls read my 1st request), as it do when it work.
2. nslookup confirmed It's reported by wingate that cannot find the IP Address.
Second, My ADSL get DNS server automatic, I think it work. because the problem will not occur in wingate server and will not occur when i don't use NAT(e.g. use www proxy server for IE) in pc behind wingate server, Even when I use NAT, sometime it will not occur and sometime it will only occur to some site(e.g. in the same time,
www.qbik.com is ok but forums.qbik.com don't work, pls read my 1st request),so I said it's not stable.
Finnally,After I have manually added DNS servers to WinGate's DNS resolver in GateKeeper, It seems the same as get DNS server automatic,
but I didn't check it carefully.
Thanks