How to set up a SMARTHOST in SunONE Messaging Server 6

This is useful if you have certain domains that you want to specify the mailservers for or if you need to send mail through another machine.

1) In the first half of the /<server root>/imta/config/imta.cnf file:
add under ! Rules to select local users:
domain.com $E$F$U%$D@smarthost-daemon

2) In the second half of the file, where you have all the channels separated by an empty line:
add:
!
! smarthost
smarthost smtp mx daemon relayhost.domain.com
smarthost-daemon

3) In the /<server root>/imta/config/job_controller.cnf file:
add:
!
[CHANNEL=smarthost]
anon_host=0
master_command=IMTA_EXE:smtp_client

4) Run /<server root>/imsimta refresh

That’s it! Now, all mail that goes to domain.com from this machine goes to relayhost.domain.com for processing.

Also, if you were supposed to use a smarthost, but didn’t set it on installation, here is where you change it.
On the channel that is used to send mail out (most likely, tcp_local)
add:
daemon relayhost.domain.com

so if your channel looks like this:
!
! tcp_local
tcp_local smtp mx single_sys remotehost inner switchchannel identnonelimited subdirs 20 maxjobs 7 pool SMTP_POOL maytlsserver maysaslserver saslswitchchannel tcp_auth
tcp-daemon

modify it so it looks like this:
!
! tcp_local
tcp_local smtp mx single_sys remotehost inner switchchannel identnonelimited subdirs 20 maxjobs 7 pool SMTP_POOL maytlsserver maysaslserver saslswitchchannel tcp_auth daemon relayhost.domain.com
tcp-daemon