We have a number of static PAT as well as policy NAT pointing services from servers and loadbalancers to the outside world on specific ports. In this case, our Postfix Mail server is accepting inbound connections fine, and sending out fine - however.
We are experiencing a number bounces from certain providers due to a SMTP X-Source-Ip being the outside interface of the ASA, thus marked as SPAM. Outbound SMTP traffic needs to returning on SMTP as the originating mapped PAT.
The current config is using mostly policy NAT w/ object groups, and is being trimmed as services and hosts get decommed (objects were imported from a diff FW). I have also tested straight static PAT for SMTP to avoid policy NAT all together. Have also tried w/o 2nd global & nat commands, and have had no luck with either configuration.
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...