mailscanner 4.2x and postfix 2.0.14 do play well together

[Julian Field]

I wouldn't advise using Postfix with MailScanner either, due to lousy
performance. Because Postfix has 1 file per message, if you want to add a
single header you have to do all the I/O to copy the entire message,
including potentially 10s of Mbytes of body text.

With sendmail and Exim, the headers are kept in a separate file. This means
that when a message doesn't need its body altering (most messages don't)
then the body can be moved to the outgoing queue via a "link and delete"
operation which doesn't involve any I/O on the body of the message at all.

So sendmail and Exim are way faster with MailScanner, due to the I/O load
being a small fraction of what it is with Postfix.

I wrote support for Postfix because people wanted it, not because I thought
it was a good idea
:-)

At 01:54 28/08/2003, you wrote:
>Hi all,
>
>Since I am evaluating new mail servers (postfix and exim) and a
>mailing list manager, I've been following discussion in the postfix
>mailing list.
>
>This is from the guy who developed postfix, recommending against
>using mailscanner, replying to my query regarding postfix and
>mailscanner:
>
>At 18:54 -0400 08/27/2003, Wietse Venema wrote:
>>Do not use mailscanner. This software accesses Postfix queue files
>>directly.  This can result in message corruption.
>
>and in a follow up, when I asked what he recommends:
>
>At 20:02 -0400 08/27/2003, Wietse Venema wrote:
>>
>>There is plenty of choice.
>>
>>Choose a product that uses a well defined protocol such as SMTP or
>>(command line + exit status). These products are more reliable,
>>because they rely on protocols that are well defined. The protocols
>>do not change, so the same scanner will work with multiple Postfix
>>versions.
>>
>>Avoid scanner systems that depend on undocumented behavior. Such
>>systems are less reliable, because they depend on internal details
>>that are easily mis-understood.  Internal details will change, so
>>the scanner that works with Postfix version X may very well be
>>broken with Postfix version X+1.
>>
>>       Wietse
>
>
>I am a novice with this, I hope it is OK to quote someone else's
>replies to me...
>
>-avi
>
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>
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>
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--
Julian Field
www.MailScanner.info
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