Slightly similar to one or two postings I have seen, we have a 2820N (Firmware 3.3.5_232201) which handles just data traffic from a remote office, including individual VPN's (Microsofts VPN, nothing 'special' like Cisco). The VPN's work absolutely fine but, occasionally, if the BB line drops or there is a 'blip' the VPN just will not reconnect without a physical reboot of the router. I have remotely accessed a users PC on the link when this has occured, they can get Internet access and ping the target VPN but it will not reconnect. Connecting using the same users credentials from our site works absolutely fine. A remote reboot of the router does not clear the problem, only a physical off/on.
Any ideas welcomed?!

I've had experience of 2600, 2800 and 2820 routers experiencing a "lock out" after a period of time. Not all router, just some. And when they do, they will continue to operate fine, but do not accept any new VPN or local connections, so you can't reboot it without using the power switch. Firmware upgrades never fixed these issues, but as it wasn't too common or too frequent, we've lived with it.

Do the VPN profiles include a ping or keep alive? This should help the unit to realise that the link failed. Or would changing the direction help? From Dial out to Dial in ? Regards, Neal

I've had experience of 2600, 2800 and 2820 routers experiencing a "lock out" after a period of time.

I have the same problem - I got around it by writing a script to reboot the router which is activated by sending an specific email message to my mail server ....