If you have two statements, one that lists a range of IPs, and one that lists just one IP, then the default will be for ASA to give out dedicated IPs for each client it can to fill up the IP range. Then once there are no more IPs available, it will start to PAT every subsequent inside host that needs to be NATed.
The number of connections one IP can support when using PAT, is roughly 65,500. It is based on the number of connections, not the number of IPs on the inside.
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...