User:Hannes Röst/postfix

Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail. You can use postfix for example to

receive email from a local program that wants to send email
receive email over SMTP (from an email client or from another server)
decide what to do with that email (e.g. deliver it locally or relay it to yet another server)
process it in a number of ways

=> See Postfix Overview for a good overview over the way a message takes when processed through postfix.

The /etc/postfix/main.cf file stores site specific Postfix configuration parameters while /etc/postfix/master.cf defines daemon processes. The Postfix Basic Configuration tutorial covers the core settings that each site needs to consider.

Basic setup

The slash after the directory in /etc/aliases says whether mbox or maildir should be used.

#/etc/aliases
# use a maildir
testuser:      /var/mail/testuser/
# use a mbox
othertestuser:      /var/mail/othertestuser

This creates a "catch-all" address for local relay if no user can be found to relay the mail to (main.config)

# /etc/postfix/main.cf 
#relay all UNDELIVERABLE email to me@domain.com
luser_relay = me@domain.com
local_recipient_maps =

Try to do that:

Postfix:25 -> ClamAV:10025 -> Postfix:10026 -> dspam:10000 -> Postfix:10027

smtp_generic_maps is a possible solution here since it only rewrite outgoing email.

Create a user, e.g. called send_for_xxx and give it a username/pw. Then use the smtp_generic_maps entry in main.cf

# main.cf
smtp_generic_maps = hash:/etc/mail/generic

to add a rewrite of the sender email address:

#/etc/mail/generic
send_for_xxx:       xxx@domain.org