We have a site to site VPN using a pair of PIX 515's in the primary site that works fine almost all the time. Once in a while the remote side cannot access anything in the primary site and it seems that doing a clear crypto and clearing the tunnel fixes the problem. in trying to discover the source of the problem, the only thing I see is the following log message:
ul 14 2009 13:41:59: %PIX-3-713235: Group = remote, IP = xxx.xxx.xxx.xxx, Attempt to send an IKE packet from standby unit. Dropping the packet!
It does not appear that this message is significant, but it's the only clue I have right now.
Has anyone experienced similar issues?