When Connected to a microsoft VPN through a Cisco IOS router
Client machines are able to connect in to the VPN successfully and access network resources, but after a period of time the VPN appears to ignore packets coming in over the VPN. The VPN connection appears to be connected from the client end, but no access to network resources is possible, including pinging servers etc.
after 30 seconds the ping to a server gives time-outs. In my case it was a NAT problem in the cisco router.
ip nat translation tcp-timeout 30
ip nat translation timeout 30
ip nat translation udp-timeout 30
ip nat translation icmp-timeout 30
i had to remove : ip nat translation tcp-timeout 30 to make it work. Now the VPN remains stable.