What kind of VPN tunnel? Are you using gre in IPSec? If you can always ping but you are having Cifs problems, I've seen mtu cause this. Ping but gradually increase the size from about 1400 bytes to see where you get maxed out. Or take the simple way out and adjust the mtu to 1420 on the interface and a tcp mss of 1380.
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...