By default the S-Series will not allow RDP traffic to be tunnel through it.
RDP uses port 3389, which is not included in the normal "allow" list of ports for CONNECT requests (which is how the client can ask for a tunnel). If you've added port 3389 (or a range including it) then you can block RDP by removing that port. If you haven't added it, then it's already blocked!
Of course, the IronPort will only block people trying to tunnel RDP traffic through it. If you want to block it outright, you'll also need to block it at your firewall if you haven't already.
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...