Last night we had an issue with an XLATE entry remaining in the XLATE table after removing an incorrect NAT. That is not the problem, once the entry was manually removed all connectivity was restored. The issue stems from the original NAT, it was put in place to resolve a problem, but broke connectivity to a seperate more important server. We removed the NAT, and connectivity was restored. 3 hours later the servers were no longer able to talk to each other once again with this error in the log: Deny TCP (no connection) from my.internal.IP.1/port to my.internal.IP.2/port flags RST on interface outside. My question is, why would the connection suddenly break after working for three hours? Also, what is the command to see the XLATE timeout period?
I'm not sure I follow exactly what order you removed/added NAT entries, but it sounds to me like the xlate for that server was still in the xlate table even when the command was removed. This will happen unless the xlate was cleared for that specific device. If you are CLI, you would use the 'clear xlate local/foreign...etc...' commands. The default for an xlate timeout is 3 hours. You can verify this by issuing 'show running-config timeout'. This will also show connection timeouts. It is possible that the connection was kept alive and timed out after 3 hours. I believe the default for connection timeout is 1 hr, however.
Anyway, again, not sure I understand fully what happened, but it does sound like either the xlate timeout or conn timeout values.
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...