Install qmail as described in INSTALL.
For each domain you want to receive mail for:
1) Put that domain name in /var/qmail/control/rctphosts
2) Put domain.com:[w.x.y.z] in /var/qmail/control/smtproutes, where w.x.y.z
is the IP address of your internal exchange server.
3) Make sure that none of these domains are listed in
/var/qmail/control/locals, or the mail will not make it to Exchange.
4) If you will also send mail from the bastion host directly, modify
defaultdomain and defaulthost to your taste (man qmail-control will tell you
where to find more info on them).
These steps will set up inbound relay for your domains; the internet
sends mail to qmail, and qmail forwards it all to Exchange.
To allow Exchange to relay out through the machine, follow the
selective relaying instructions at
http://www.palomine.net/qmail/selectiverelay.html.
--
gowen -- Greg Owen -- [EMAIL PROTECTED]