We are having issues with our IPSEC tunnel not working. It was working previously for a while but then all of a sudden it stopped working. We have a Windows 2008 R2 standard server (source) that will initiate the tunnel to a Windows 2003 server (destination). We have network monitor installed on both servers and see the traffic leaving the Windows 2008 server and arriving at the Windows 2003 server. However, we do not see return traffic leaving the Windows 2003 going back. There is a Cisco ASA firewall that sits b/t these servers and it has rules in place to allow communication b/t the servers. We are not seeing any traffic being dropped by the Cisco ASA firewall. Thanks for any help given.

Using Cisco IPS Sensor Software Version 6.x, the Cisco AIP-SSM combines inline prevention services with innovative technologies to improve accuracy. The result is total confidence in the protection offered by your intrusion prevention system (IPS) solution, without the fear of legitimate traffic being dropped. When deployed within Cisco ASA 5500 Series appliances, the AIP-SSM offers comprehensive protection of your network by collaborating with other network security resources, providing a proactive approach to protecting your network.Mark Van Deibert

Hi, Any errors logs in the Event Viewer? In addition, you may run the IPSec diagnostic tool to check for network if any errors on both Windows 2003 and Windows 2008. For detailed information, please check the following KB article: The Microsoft IPsec Diagnostic Tool is available for Windows Server 2008, for Windows Vista, for Windows Server 2003, and for Windows XP http://support.microsoft.com/kb/943862 Also check the Windows Firewall settings on both sides. Please refer to the below link. Security rules for Windows Firewall and for IPsec-based connections in Windows Vista and in Windows Server 2008 http://support.microsoft.com/kb/942957 Best Regards, Aiden Aiden Cao TechNet Community Support