Good day. We have cisco 3825 router terminating l2l ipsec vpn from about 20 remote sites. Sometimes (once - twice a week) the tunnel with random site goes down and cannot be reestablished. The strange thing is that i can't see any traces of activity in logs with debug isakmp and debug ipsec from this remote site. Other Vpn tunnels are working fine. No hang crypto sessions or sa's. The only way to reestablish the tunnel is rebooting the router.
Thanks in advance , Dmitry.