We are having trouble with a site to site VPN as follows:
In this example we will use site A and site B. We have a Pix 515E at site A and a Cisco 1801 at site B with a site to site between the two. If we ping from site B to site A then the tunnel comes up and we can ping in either direction and traffic flows in both directions. If we try to ping from site A to site B to bring up the tunnel then the pings will fail. So, put another way we can only initiate the tunnel from site B.
TROUBLE SHOOTING SO FAR
We have checked the NAT and ACLs, all of which seem fine and seem comparable with other configs on working systems in the field.
Anyone have any suggestions or possible causes?