I have a c831 router that is having a few problems rebooting itself. So had another 831 that I was not using so I copied the startup-config from the failing device to the other and swapped them out. Most everything seems to work except I have a Microsoft server inside the network that is running a basic VPN with pptp and that no longer works. The main difference between the 2 routers is the IOS - the original one is 12.3 and the newer one is 12.4. I have comlpetely removed the access-lists from the interfaces to be sure that nothing is being blocked there as well as combed my syslogd logs to verify that there were no GRE blocks in there. This setup is behind a little DSL modem but is running nothing terribly complex. Anyone know any differences between IOS version 12.3 and 12.4 that might be causing this or anything else I might have missed? It seemed like such a simple thing to fix and has become a huge time-killer. thanks for any ideas.