I have just replaced a faulty AG041 with an AG241 router. I have a VPN connection to a PIX firewall that was working correctly prior to the swap. Since the router replacement I get very random VPN connectivity. Sometimes it works but most times it doesn't!
A debug on the PIX says
"ISAKMP: reserved not zero on payload 5!"
according to Cisco, this means that the ISAKMP keys do not match. Rekey/reset in order to ensure accuracy.
I have removed the configuration from the PIX and re-added it, I have also re-configured the VPN on the AG241 but I still get this problem.