I've spent a decent amount of time hardening cisco routers and switches and I have never been able to fool nmap. Even when the router/switch is locked down as much as possible, nmap will fingerprint it every time. All I do is not answer pings, which probably gets most script-kiddies off my back.
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...