Here is a quote from Cisco documentation regarding the ASA 5505 Licensing
In routed mode, hosts on the inside (Business and Home VLANs) count towards the limit when they communicate with the outside (Internet VLAN), including when the inside initiates a connection to the outside as well as when the outside initiates a connection to the inside. Note that even when the outside initiates a connection to the inside, outside hosts are not counted towards the limit; only the inside hosts count. Hosts that initiate traffic between Business and Home are also not counted towards the limit. The interface associated with the default route is considered to be the outside Internet interface. If there is no default route, hosts on all interfaces are counted toward the limit. In transparent mode, the interface with the lowest number of hosts is counted towards the host limit.
See the show local-host command to view host limits.
So as you can see, if you for example have a Base License ASA5505 with 3 Vlans (DMZ, Restricted) then you should be able to use 10 hosts behind your LAN and DMZ interfaces in total if they all need to access the Internet behind the WAN link. Host behind the WAN interface are not counted towards the 10 user limit.
Also the command mentioned in the above quote is a great way to keep track of the host limit.
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...
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