I am not sure if the output of the capture is saying some outside\Internet IP address was able to open port 25 on 216.a.b.c or simply attempted to open the port. What I do know, when I try to telnet to port 25 from the Internet (or port 80 or 443) I am unable to open the port.
It is worth noting that I can ping 216.a.b.c from the Internet, so it looks like the static NAT is working to some extent, but I am unable to open the three ports.
Is there another way to determining the root cause of this issue in addition to "capture"?
I have posted the config in the first message of this thread. Again, I am followed the same example as here:
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...