ipnat on same interface?

[Lars-Johan Liman <liman%autonomica.se@localhost>]

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/
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