Hi Nikita
Is this an Active Directory environment ?
If you want to configure WinGate to work in an Win2000 Active Directory I would suggest you take a look at the WinGate knowledge base on how to configure this.
http://support.qbik.com/index.php?_a=knowledgebase
Essentially in this scenario your clients DNS settings should point to the DNS server, for Active Directory stuff and inturn the DNS servers forward lookup setting should be set to the WinGate internal IP so that Internet requests will be forwarded to WinGate. DNS and DHCP services on the WinGate machine should be disabled as not to cause confusion with the DNS and DHCP servers in the AD.
Regards
Erwin