12 years as a firewall guy... and this is a first for me.
I have a request to allow firewall access to an app that apparently uses tcp port 0. I thought it didn't exist... but good-ol' google proved that wrong. I did find this comment: " Port 0 is officially a reserved port in TCP/IP networking, meaning that it should not be used for any TCP or UDP network communications. "
Just out of curiosity, anyone implemented an acl using port 0 before? Any issues on the ASA side?
The FWSM system log message ID is the same agian (500004).
This syslog message would be generated when port 0 destined traffic is already allowed through the firewall (not within an acl permitting port 0 of course but a more generic acl that does not contain the port number and permits in general ip/tcp traffic).
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...