I run two PIX515e in FO and we seem to loose IPsec at random times and the only way to get it to work again is to reload both PIXs. (Having said the I do think that once it corrected itself after 40 minutes but was away so can't be sure).
We have one l2l and several r2 ipsec tunnels configured and when this happens (randomly) the l2l tunnels can complete phase 1 but not phase 2 and the r2 connection attempt either don't show anything at the pix or show (no connection) errors.
I sent this to Cisco and they said that it was something to do with out of sync packets coming from the remote peer.
Does this mean anything to anyone? It happened again last night (yawn) and I have been through the logs but I can't seem to see any entries that are significant.
I'd put configs and logs on here but I'm not sure what is relevan (I pretty sure the config is OK since Cisco have checked it).