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List:       postfix-users
Subject:    Re: postfix milter body chunk length
From:       Wietse Venema <wietse () porcupine ! org>
Date:       2019-08-16 13:50:45
Message-ID: 4694Td0s4SzJrNt () spike ! porcupine ! org
[Download RAW message or body]

Viktor Dukhovni:
> > On Aug 16, 2019, at 10:33 PM, Matthias Schneider <matthias.schneider@rmail.de> \
> > wrote: 
> > I was wondering why the transfer of a 100mb mail to my milter application was \
> > slow, i found the bottleneck in the body chunk transfer. 
> > The maximum packet length seems to be fixed to 64k, it would be great if we could \
> > make that configurable in postfix (uint32 is possible).
> 
> https://github.com/avar/sendmail-pmilter/blob/master/doc/milter-protocol.txt#L182-L213
>  
> http://ftp.sendmail.org/KNOWNBUGS
> 
> * milter communication fails if a single header is larger than 64K.
> 
> If a single header is larger than 64KB (which is not possible in the
> default configuration) then it cannot be transferred in one block to
> libmilter and hence the communication fails.  This can be avoided by
> increasing the constant MILTER_CHUNK_SIZE in
> include/libmilter/mfdef.h and recompiling sendmail, libmilter, and
> all (statically linked) milters (or by using undocumented compile
> time options: _FFR_MAXDATASIZE/_FFR_MDS_NEGOTIATE; you have to
> read the source code in order to use these properly).

On the Postfix side, edit src/milter/milter8.c and update its
MILTER_CHUNK_SIZE definition accordingly. It's only compile-time
configurable in Postfix, because it's only compile-time configurable
in libmilter.

	Wietse


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