> I know inbound, 1:1 NATs. Can You clear me, how works outbound NAT? I ment
> that contrariwise as inbound (more public IP to one internal - f.e.server),
> but the setting is different...
I'll take a stab at it. 1:1 nat maps one outside address to one inside
address. One address is translated to another. 1:many is in effect PAT
(port address translation) where an entire subnet (say 10.0.1.x) on the
inside interface can be translated to a single public address (say
220.127.116.11). Relationships to determine where replies are sent back to
which client inside are mapped by port number. So say 10.0.1.3 makes an
outbound HTTP request to a public server, he hits the router/firewall
where his connection out is assigned to TCP port 35555. When a reply
comes back from the remote web server to port 35555, the router/firewall
will accept that response and forward it to 10.0.1.3. Sort of a virtual
mapping by port.