We have a 2811 edge router in our office, we then have a number of users who use PPTP to VPN to a different office from our local LAN. This works and connects fine but the connections dropout randomly. The dropouts can occur after 5 minutes, sometimes half an hour, always random times. We have a backup connection over a different ISP which works fine and always keeps the sessions stable, so I have to setup a static route to send the traffic destined to our other office over the backup link, this is obviously not an ideal process if that link fails.
I have tried changing some NAT translastion timeouts and this seems to have no effect (to be expected as the default should be more than enough). I also tried to setup a static NAT translation at one point to see whether that would change anything and this did not.
Does anyone have any ideas at what could be causing the random drop outs? As soon as you hit "redial" the session reconnects.
The clients are using the Microsoft built-in VPN client. It doesn't seem to be a client issue as the problem only occurs when using the specific primary connection, works fine on the other link as well as at home.
Can post a config if required.
Any help would be much appreciated