Author: Sheldon Hearn Date: To: swhite CC: exim-users Subject: Re: ??: [Exim] Exim as transparent "proxy"?
On Sat, 01 Dec 2001 21:23:18 +0200, swhite@??? wrote:
| Nice idea but no Linux here. Free/OpenBSD and cisco routers. I
| know I can redirect the packets with a policy route map in the
| cisco boxen... getting exim on BSD to accept them is the trick.
I don't understand the problem. You just want Exim on box X to accept
and handle SMTP sessions intended for box Y, right?
Unless you're using unusual SMTP extensions, the IP address of the server
isn't necessary in the SMTP session.
So your problem seems a simple case of IP masquerading. You just need
box X to rewrite packets received for port 25 to port 25 on box Y, and
know that packets _from_ port 25 on box Y need to be sent back to the
correct client IP+port.
In FreeBSD, you can use either natd(8) or ipnat(4) for this kind of port
forwaring. The online FreeBSD handbook should provide you with more
than enough information on masquerading.
