Hello folks -
I built a site-2-site VPN between two Cisco routers, namely R1 and R2. R1 is a 3845 and so is R2. R1 is directly connected to a DSL modem, and R2 is sitting behind a firewall. I have opened ports UDP 4500, ESP and port 500 on the firewall to let the VPN traffic through.
When interesting traffic is sent across the tunnel, the tunnel comes up and pings from either end work fine. However, none of the applications (Outlook, SAP etc.) connect to the servers. The servers are also in a subnet behind the firewall (same firewall as R2).
After doing some reading, everything points towards an MTU issue. However, I am not sure where to change the MTU. On the workstations or the routers?
If you guys can think of other troubleshooting steps, that would be great.
Thanks for the help.