Well one of the biggest difference is that the PIX has a limited number of things it can look for when used as an IDS. About 50 or so signatures. A true IDS solution like the 4200 series has hundreds of signatures it can look for and more signatures are added every few weeks. The PIX signatures are updated very infrequently. If you have a SmartNet account you are eligible for both software and signature updates for "free" (Well you had to pay for the SmartNet right?) If you do not have a SmartNet then but you do have a CCO account then technically you can get the signature updates off the Cisco site for free.
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...