I want to establish GRE over IPsec tunnel between four branch offices and head office. At branch offices, I have 1841 router with Advanced Security software. At head office, I have a ASA5510 7.2 as frontend with one public IP addres and 1841 router behind it in private address space. Since ASA is not supporting GRE tunnels, can ASA be endpoint for GRE over IPsec? If not, can ASA pass this tunnel to the 1841 router behind it, so 1841 would be logical tunnel endpoint? What should I pay attention? Should both ASA and every 1841 support NAT-T, or just ASA?
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...