We are currently experiencing a very peculiar problem with a IPsec VPN we have setup between 2 sites using Cisco 878 routers connected to 2MB SDSL circuits. The VPN comes up perfectly fine. We can ping across the 2 networks. However, nothing else works. When I try to access a server from one network to the other, I cannot telnet to port 25, 3389 or any other port. The access-list allows full IP. I have tried Drayteks routers to do the VPN and they work i.e. I can see all the relevant ports and they are open. The problem also occurs when using GRE to creat the VPN.
Therefore the Cisco routers are blocking the ports and I cannot see the reason why.
Please can someone help asap. Configs are attached.