I've had a set of PIX 506E boxes holding an IPSEC tunnel for a good year or so without a hitch. Today, the tunnel dropped and I lost access to the remote site. The local PIX can only ping devices on the local [inside] subnet and all nodes on all my other subnets can't find a route to the PIX. On the local gateway, I can ping the PIX, but can't traceroute to it. I also ran an ICMP debug and could see when remote nodes ping, but the reply doesn't leave the box.
Nothing has changed, routes all look good, i've reset everything -- no luck at all. Any idea what may be happening? I have a feeling it's a basic issue that looks more complex that it is, but i'm stumped at this point.
Any help would be greatly appreciated!