The problem of overlapping address space can be solved using enhanced NAT/ bi-directional nat, which allows to to apply the NAT and global commands to the outside and inside interfaces respectively. The earlier restriction wrt placement of these commands are not valid any more. You could also see a related document at http://www.cisco.com/warp/public/707/vpn_pix_private.html.
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...