Configure your FTP server to send it's public IP address in the PASV response and define a static PASV port range. You must then open the PASV range inbound in addition to port 990 (assuming you're using FTPS on the default port) for the clients who need to connection. If you're running FTPS on port 21, you'll need to make sure that FTP inspection is disabled.
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...