Re: ipnat on same interface?

[jmitchel%bigjar.com@localhost]

If the connections are TCP only, you should check out rinetd in pkgsrc.
It's lightweight and can essentially redirect traffic from one IP to
another by accepting a connection on one IP, creating a second connection
to an external IP and passing traffic between them. It's not technically
NAT or port forwarding, but it would do what you're asking.

> Hi!
>
> Has anyone succeeded in configuring ipnat to do NAT/port forwarding
> to/from the same network interface? I have a service where I want to
> have a single frontend machine with a public IP address, and I want to
> avoid disclosing the public IP addressses of the actual (say three)
> machines that actually perform the service. I want to distinguish the
> actual machines by selecting ports on the frontend machine. The frontend
> machine only has one interface, so the packets need to go in and out
> through the same interface.
>
> call @frontend:1001  --> NAT -->  reach @actual1:99
> call @frontend:1002  --> NAT -->  reach @actual2:99
> call @frontend:1003  --> NAT -->  reach @actual3:99
>
> Any hints?
>
> ... or, is this simply not possible, due to the physics of ipf/ipnat?
>
> (I just blew my remote test box off the water, so "that was obviously
> not the right way to do it" ... ;-) ;-) I'll be more careful next time,
> I promise ... ;-)
>
>                               Cheers,
>                                 /Lars-Johan Liman
> #----------------------------------------------------------------------
> # Lars-Johan Liman, M.Sc.   ! E-mail/SIP/Jabber: liman%autonomica.se@localhost
> # Senior Systems Specialist ! Tel: +46 8 - 562 860 12
> # Autonomica AB, Stockholm  ! http://www.autonomica.se/
> #----------------------------------------------------------------------
>