Hi, I am trying to understand how ASA treats GRE traffic. I have a application that needs to set a GRE tunnel between two (internal) WAN acceleration devices across Internet via IPsec VPN, and polycom video traffic is carried by this GRE tunnel for WAN acceleration through PBR. The video conference worked fine if the datapath is going thorough normal path (aka, no WAN optimization), but when the video conference traffic is diverted to this GRE tunnel, I can not even get the dial tone on the other side.
I am suspecting that video conference traffic is undergoing un-symmetric routing and ASA is dropping the return traffic if the return traffic is not in GRE. Now here is my question: How ASA processes GRE traffic? does it look deep inside the GRE packet to see whether it is a TCP packet and then randomize the sequence number? or it just transparently route the packet out to different interface exactly like a router would do?