I am not sure if you are sending mails to yahoo, you should be worrying about smtproutes as it handles incoming mails (destined for your internal domains). I see you also removed the sending IP so I am assuming its a public Ip address maybe. Normally you send mail froma trusted IP address through the Ironport, this is called relaying. If its a remote location you can use authentication, but if this is a local server that you just want to relay mail through the Ironport, then you need to add this IP address in your relaylist sender group (Mail Policies - HAT Overview), make sure your outgoing listener is selected and click on the $RELAYLIST and add the IP there. From now on It will be treated as outgoing and not incoming.
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...