Postfix and MailScanner

[Mark Sapiro]

On 05/15/2015 03:40 PM, Kevin Miller wrote:
> I've been using MailScanner with sendmail historically, but have made the leap to postfix.  With sendmail, I had to disable the init script (chkconfig sendmail off) so it didn't start and enable the MailScanner init script (which started sendmail).  The instructions on the web page don't mention disabling the postfix - they just say to start MailScanner and it should handle starting postfix.  Do I need to do anything special to insure that MailScanner starts before and in place of postfix?


I've been running MailScanner 4.84.6 (and prior) on CentOS 5 for a long
time. When this was installed with Jules' install, it installed a
/etc/init.d/MailScanner script which started and stopped Postfix along
with MailScanner.

I am in the process of preparing a new Ubuntu 14.04.2 server to replace
the old one and have installed the current 4.85.2-2 and then upgraded to
4.85.2-3.

This package installed a MailScanner init.d script that doesn't stop and
start Postfix, so they are independent 'service' scripts.

This is more or less OK because Postfix and MailScanner communicate by
queueing. Postfix when configured for MailScanner receives a message and
queues it in it's hold queue. MailScanner processes messages from
Postfix's hold queue, and if they are to be delivered, requeues them in
Postfix's active (I think) queue, and Postfix takes them from there. If
Postfix is running and MailScanner isn't, mail will sit in the hold
queue until MailScanner starts. If Mailscanner is running and Postfix
isn't, whatever residual mail that MailScanner processes will just be
queued for Postfix when it starts.

Thus, both Postfix and MailScanner have to be running for mail to flow,
but startup/shutdown timing isn't critical.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan