My router is doing both static NAT and dynamic from a pool of public addresses. When I execute a sh ip nat trans command, the output shows most of my Inside local and global addresses, both static and dynamic, with a a following tcp port of 21. Why is that? Will I need to consider this when building my access-lists?
I realize that 21 is the standard representation for FTP control, but every single nat translation on the inside has the :21 referenced after it and there is simply no possible way that every user on the network has initiated a file transfer? Any other thoughts or possibilities?
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...