postfix and mailscanner

Antony Stone Antony.Stone at
Wed Dec 13 22:58:49 UTC 2017

On Wednesday 13 December 2017 at 23:36:54, Jerry Benton 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.

That's how it works with sendmail and Exim, too, so why do the postfix people 
say that this "will result in corruption or loss of mail"?

Has this been verified?


> -----Original Message-----
> From: MailScanner
> [ at lists.mailscanner.i
> n fo] On Behalf Of Maarten
> Sent: Wednesday, December 13, 2017 17:34
> To: MailScanner Discussion <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?

The first fifty percent of an engineering project takes ninety percent of the 
time, and the remaining fifty percent takes another ninety percent of the time.

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