I'm having two odd problems with a 2821 that is used as a firewall. I'll describe one of them.
Every few days, I can not access a server on the internet at port 1055. Running a 'clear ip nat trans *' does not fix the issue. Strangely enough, after reloading the 2821, access from the internal network to the internet server at port 1055 works again.
Additionally, while the problem is occurring, any other port that is listening on the internet server is accessible, just not 1055. A reload fixes the issue.
Also, sh ip nat trans only has about 1000 lines when the problem is occurring.
Upgrading didn't help. The problem magically went away. I'm still not sure what changed. I narrowed it down to a handful of lines in the Cisco config, though none of them should have helped the issue from what I could tell.
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...