we are using a VPN connection between a LINUX client (SuSE 7.3) and a Concentrator. We are facing a system crash randomly when establishing and disconnecting the tunnel, a part of the message on the console is "module cvpnd" "Kernel panic in Interrupt handler" "killing interrupt handler", but only when the system is quit busy. To investigate this behaviour, we implemented some test-scripts which give the system a heavy CPU load. We tried different kinds of connection (ISDN, DSL), client versions 3.6.3 and 3.7, different Kernels and drivers and PCs (also from different manufacturers).
The following would provide some details on how you can troubleshoot this problem.
LINUX PANIC OUTPUT:
You may not be seeing the panic output, because having X window running may be hiding the kernel panic messages. It may be panicking, but because X is running, you may not see the panic messages.
One trick that helps find out if a kernel panic is occurring, is to setup a serial port as a terminal, and using a terminal emulator running on a separate machine to monitor that terminal when a system lockup occurs.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...