There is agroup of network conected to a Cisco 1811 ISR through site to site VPN. Everything goes fine but after 5 or 6 hours of traffic , the users can not reach any more the servers and even when the routers are restarded , the problem remain the same. Only when the server is restarted , the users can log in it. This happen only from users behind the routers. The other users that are in a bridge network , dont have any problem. In routers are configured DLSW for SNA routing.