This seems to be the MTU, maybe lowering it on the actual server migth help, also try lowering it using Dr. TCP aswell, sometimes it fixes it right away, for further troubleshooting feel free to contact the TAC.
Hi, We have also been having a problem similar to this and I am happy to say that we have fixed the problem by uninstalling any old clients and installing vpn client 3.6. We also left the mtu setting at it's new default, 1300. If you read the release notes, it changes the way it interacts with Windows XP and fixes a few more issues. Give it a try.
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...