You connect to a server that is running Microsoft Forefront Threat Management Gateway 2010 by using a VPN client. Immediately after the client is connected, the client may be unable to perform name resolution queries against an internal Domain Name System (DNS) server. However, shortly after the client is connected, the client can perform DNS queries against the DNS server as expected.
To resolve this problem, install the service pack that is described in the following Microsoft Knowledge Base article:
2555840 Description of Service Pack 2 for Microsoft Forefront Threat Management Gateway 2010
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates