Article ID: 2780562 - View products that this article applies to.
Consider the following scenarios.
In these scenarios, the establishment of the client's PPTP connection may be unsuccessful because Forefront TMG 2010 drops the PPTP server's Generic Routing Encapsulation (GRE) packets.
The issue occurs because of incorrect handling of GRE packets in NAT mode when an IPSec-based site-to-site VPN is configured in Forefront TMG.
To resolve this problem, install the hotfix package that is described in the following article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/2735208/ )Rollup 3 for Forefront Threat Management Gateway (TMG) 2010 Service Pack 2
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:
(https://support.microsoft.com/kb/824684/ )Description of the standard terminology that is used to describe Microsoft software updates
Article ID: 2780562 - Last Review: January 21, 2013 - Revision: 3.0