I am running a RRAS box and my solution was to NAT the outside interface of the RRAS box to a public IP (126.96.36.199 in my example) then add the following lines to my outside access-list. You have to remember to allow GRE. The server is located in my DMZ so I nat from outside to dmz. works like a champ. We usually have 20+ people connected at any give time on this server.
access-list outside_access_in extended permit gre any host 188.8.131.52
access-list outside_access_in extended permit tcp any host 184.108.40.206 eq pptp
YOu should be able to establish more than one connection. The scenario you are talking about was in old versions of PIX 6.1 where if a client behind the PIX requires to initiate a PPTP connection to the outside you would need to create a static NAT for this client and thus can support one connection.
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...