postfix and mailscanner

Jerry Benton jerry.benton at
Thu Dec 14 00:05:19 UTC 2017

It is possible. I have written one for Mailborder v5 in PHP. I have gone so far as to write an entire new scanning engine in C and PHP as well for Mailborder v5. The milter won’t work with MailScanner because it is designed to work with the upcoming Mailborder scan engine, but I can share some information to help build a MailScanner milter. 




Jerry Benton

+1   (843) 800-8605

+44 (020) 3883-8605


From: MailScanner [ at] On Behalf Of Shawn Iverson
Sent: Wednesday, December 13, 2017 18:50
To: MailScanner Discussion <mailscanner at>
Subject: Re: postfix and mailscanner


For anyone curious, I am researching creating a mailscanner milter for postfix.  I have gotten as far to conclude it is possible and that it might bring additional functionality when using postfix and mailscanner together.  For example, it would be possible to reject a message for various reasons and still have detailed reports on the messages.  It would also be possible to have more granular whitelisting capabilities (virus scan only, spam scan only, no scan, etc.).  It is a ways off, but I've been looking at milter code on various things for a while.


On Wed, Dec 13, 2017 at 5:36 PM, Jerry Benton <jerry.benton at <mailto:jerry.benton at> > wrote:

Because MailScanner does not use a proper milter for Postfix. Instead, it
gets the email from a hold directory and drops it back in the Postfix queue.

This is how it is supposed to work:

Postfix > milter > hold > scan > injection to Postfix > delivery

This is how it actually works:

Postfix > hold > scan > drop into Postfix

Technically, this is incorrect.

Jerry Benton <> 
+1 (843) 800-8605 <tel:%2B1%20%20%20%28843%29%20800-8605> 
+44 (020) 3883-8605 <tel:%2B44%20%28020%29%203883-8605> 

-----Original Message-----
From: MailScanner
[mailto:mailscanner-bounces+jerry.benton <mailto:mailscanner-bounces%2Bjerry.benton> at < at> 
fo] On Behalf Of Maarten
Sent: Wednesday, December 13, 2017 17:34
To: MailScanner Discussion <mailscanner at <mailto:mailscanner at> >
Subject: postfix and mailscanner

Don't want to start a flame war here, but just a question, why does <>  advise against using mailscanner? Saw the following on the
postfix website:

mailscanner: system, works with Postfix and other MTAs. WARNING: This
software uses unsupported methods to manipulate Postfix queue files
directly. This will result in corruption or loss of mail. The mailscanner
authors have sofar refused to discuss a proper access API or protocol.

When reading through mailinglists it seems that some mails can get lost as
in how mailscanner handles mail from the postfix mailqueue, and that it's
safer to use one of the virus/spam/content filters that that uses the SMTP
proxy interface or the Milter Interface. I wouldn't know if this is true or
how to know if any mails every got lost(is there a way to know of having
lost mails), but have there ever been talks between postfix devs and
mailscanner devs about this?

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Shawn Iverson, CETL

Director of Technology

Rush County Schools

765-932-3901 x1171

iversons at <mailto:iversons at> 


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