Without seeing a config or syslog, I am more or less guessing here but my years of experience ;) would tell me that you are probably bumping up against the conn timer on the PIX. The PIX will tear a connection down if left idle for more than an hour (by default). You may want to try bumping this value up and seeing if that helps. If it does not, you will need to setup a syslog server (if you do not already have one) and find out why the PIX is tearing the SSH connection down.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...