Re: ESMTP CHUNKING

[Wietse Venema]

J Doe:
> Hi,
>
> I have been reading about the ESMTP CHUNKING extension (RFC 3030),
> after noticing that both Hotmail and Gmail advertise it on EHLO.
>
> I checked the Postfix man pages (man 5 postconf), as well as the
> Postfix documentation at postfix.org [1] and can?t see any
> documentation related to it.

Unfortunately, Postfix documentation can only describe what is
supported. Describing all the things that aren't supported would
not be practical.

> Some Googling of the mail archives showed posts from 2014, while
> another Google showed a reference [2] to Postfix from 2017:
>
> ?IMSVA (SMTP server) uses Postfix as its MTA, which doesn?t
> support CHUNKING?
>
> Given Postfix?s excellent security track record, was this extension
> not implemented due to security concerns or is it obsolete (I
> checked the RFC and didn?t see a notice of being obsolete), and
> Hotmail and Gmail advertise it for legacy support ?

Every (software) feature has a non-zero cost, and resources are
finite.

Wietser

Re: ESMTP CHUNKING

[Viktor Dukhovni]

> On Mar 1, 2018, at 3:42 PM, J Doe  wrote:
> 
> I have been reading about the ESMTP CHUNKING extension (RFC 3030), after 
> noticing that both Hotmail and Gmail advertise it on EHLO.  
> 
> I checked the Postfix man pages (man 5 postconf), as well as the Postfix 
> documentation at postfix.org [1] and can’t see any documentation related to 
> it.

There is little need for CHUNKING.  It is unnecessary complexity for rather 
modest
data compression (avoiding base64 encoding when the message originates from an 
MUA
that supports BINARYMIME and CHUNKING and the same is true of every MTA along 
the
path).

Exim implemented chunking and had a long string of bugs until they ironed out 
all
the issues.  In Postfix my sense is that it is not a worthwhile feature.

-- 
Viktor.