We had a lots of customers reporting that after installing MS11-030 ( http://support.microsoft.com/kb/2509553 ), RRAS from time to time started to hang.
Typical symptom was that VPN connections were no longer possible; the RRAS service could not even be restarted. Only solution was a full reboot.
The good news is that a fix is released for the underlying issue:
Known issues that occur when you install update 2509553 for Windows Server 2003
With this fix, the hang should no longer occur.
Authors Balint Toth Support Escalation Engineer Microsoft CSS Forefront Edge Team
Technical Reviewer Eric Detoc Escalation Engineer Microsoft CSS Forefront Edge Team