I forgot to update this Q last friday after I've got it up and running. Problem was that our VPNC is in a DMZ. The firewall had a route in place which screwed up the return-route from the VPNC to the PIX; no traffic ever returned to the initiating PIX.
After removing that faulty route in the firewall, everything worked like a charm.
Strange thing was that we have more of such VPN-tunnels in place, but only this one gave problems.
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...