Network problem in W2K3 Server + Active Directory

Hello,
I installed W2K3 server on machine and all works fine. I have 2 network
adapters. One for local network and one for internet. I use Winroute for NAT
and mail administration. All works fine. Next I want install Active
Directory. I use AD wizard which install DNS and AD. All works fine but in
about 4 hours (sometime in later sometime sooner) my internet conection does
not work. I must change IP adres of network adapter for internet connection
and then change it back and all works fine. In protocols I see in SYSTEM
folder this errors : 8015, 2505, 8035. Can someone PLEASE help me?

 

Having a look around technet led me to this article which isn't exactly what you are getting but leads me to this question:

• How are you connecting the two network connections to your internal network, and the internet? If you are connecting both network cards to the same hub or physical network it may be confusing your server.

8035 is a browser election process . How many servers do you have on your network? If only one, this too points to a NetBIOS problem (although it can be a common event on some network setups)

8015 points to multiple instances of a NetBIOS name on the network (See this article - that led me to the link above ).

The more I look at this, the more I think the server is seeing itself twice, perhaps because the network cards are physically connected.