duplicate ipadresses by intention

["Gerald Leier" <gl_(_at_)_revolto_(_dot_)_at>]

hi :)

i recently set up a obsd fw as a adsl fw/router to
protect my workstation and speedup(cbq) the network-
connectivity.

short and stylish:

 anyone a idea how i can have a workstation behind
 a router have the same ipadress assigned like the
 gateway itself ?

the long story:

i am not a typical gamer, but from time to time id
like to play a round quake3 :) well, the problem i
ran into is related to this game. and the following
strange ip setup i desire is because of that game.

playing behind nat routers isnt working that good because
of some software namend punkbuster which "registers" the ip
(in my case. a private one) of the computer the game is
running on on some servers(to prevent cheating..whatever).

now with that private ip registered and the official ip
i got from my providers dhcp servers, i dont have much fun
playing because they dont match, i cant connect to 90% of
the available gameservers. (server may respond like hey
66.66.66.66 you havent registered yet because for the server
i am 192.168.1.10)

now i thought about how it could be possible to have
the same ip-adress on my firewalls external interface
and on the nic of the workstation behind it.

another thing to mention is that i have to use a pptp connection to get
connected to the internet. the offcial ip is also assigned to firewalls
ppp0 iface.

has anyone a idea how/if this could be accomplished ? maybe with
bridging support ? some wild double source adress translation ?
black voodoo magic ? :)

thanks for any ideas
 gerald