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 From:  "Sancho2k.net Lists" <lists at sancho2k dot net>
 To:  "M.K." <kraus at seznam dot cz>
 Cc:  Monovall Lists <m0n0wall at lists dot m0n0 dot ch>
 Subject:  Re: [m0n0wall] How works Outbound NAT?
 Date:  Tue, 09 Dec 2003 17:16:03 -0700
M.K. wrote:

> Hi,
> 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 Relationships to determine where replies are sent back to 
which client inside are mapped by port number. So say 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 Sort of a virtual 
mapping by port.