Hello I'm getting quite a bit of spam from email address where the domain cannot be verified. I've tried creating a HAT rule that rejected any email where the Reverse lookup could not verify the DNS. The problem here is it seems SPF records can cause the lookup to fail so you reject valid emails. Would setting up SPF verification correct this? I'd like to get emails from companies using valid SPF records but also block spammers trying to bounce email off servers to hide the actual sending address. I hope this makes sense.
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...