[CentOS] MailScanner With One vs Two Postfix Instances

Sat Apr 9 21:32:00 UTC 2005
Kennedy Clark <hkclark at gmail.com>

An interesting point came up while recently discussing my Postfix
virtual_alias issues with the MailScanner list.  Apparently there is
some risk with the "two instances of postfix" approach described in: 

It sounds like Postfix and MailScanner can step on each other in the
deferred queue.  They recommended the single Postfix instance "hold"
mechanism recommended here:

Here are the steps I used to convert:

1) service MailScanner stop

2) Edit MailScanner.conf and change 
      Incoming Queue Dir = /var/spool/postfix.in/deferred
      Incoming Queue Dir = /var/spool/postfix/hold

3) Rename /etc/postfix.in to /etc/postfix.old-in

4) Rename /var/spool/postfix.in to /var/spool/postifx.old-in

5) Edit /etc/postfix/master.cf and uncomment the "smtp inet n - n - -
smtpd" that was commented out in Step #12 of the 2-step instructions

6) Edit /etc/postfix/main.cf and add:
        header_checks = regexp:/etc/postfix/header_checks

7) Create /etc/postfix/header_checks containing:
        /^Received:/ HOLD 

8) service MailScanner start

And you should be back in business.  Note that the
/etc/init.d/MailScanner script still references both an in and out
Postfix instance; however, in looking at the code, once
/etc/postfix.in is gone/renamed the "in" startup action becomes a

I should also point out that there is absolutely NO implied criticism
of the SUPERB guides Johnny has put out.  I have found them to be
extremely helpful -- thanks, Johnny!