If it fails then it probably won't be passing any traffic. There's no way it's just going to start passing traffic in the clear, it either goes through the box and get's encrypted or it doesn't go through at all. I can't possibly imagine a software failure where all the encryption routines suddenly get bypassed, it just couldn't happen.
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...