Yes it is for allowing that network mgmt access to fw, what seems strange to me is that you have to connect to a core switch to then telnet to the firewall, what device is routing 192.168.133.0/24 network , can you from the firewall ping any host to this net?
can you post sanatized config , omit public ip info.
Also if you are accessing from 192.168.133.0 of 172.30.0.0 or 172.20.0.0 networks from that source host try a telnet test to either th the ip address of the inside interface of the firewall or management0/0 interface.
if you get black screen on each of the test we know connectivity is there to the freiwall on secure port 443.
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...