dovecot - Sep 2018 - Dovecot submission announces CHUNKING but backend Postfix does not support it

Hello,

I'm setting up Dovecot 2.3.2.1 as a submission proxy to a Postfix 
backend server. Dovecot announces CHUNKING, but the Postfix backend does 
not support (or announce) it.

HELO from Postfix:

   220 backend.mydomain.com ESMTP Postfix (Ubuntu)
   ehlo test
   250-backend.mydomain.com
   250-PIPELINING
   250-SIZE 104857600
   250-VRFY
   250-ETRN
   250-STARTTLS
   250-ENHANCEDSTATUSCODES
   250-8BITMIME
   250 DSN


HELO from Dovecot proxy:

   220 proxy.mydomain.com Dovecot ready.
   ehlo test
   250-proxy.mydomain.com
   250-8BITMIME
   250-AUTH PLAIN LOGIN
   250-BURL imap
   250-CHUNKING
   250-ENHANCEDSTATUSCODES
   250-SIZE
   250-STARTTLS
   250 PIPELINING


When a client sends BDAT, Postfix closes the connection. Here's a log 
snippet from Postfix:

   < MAIL FROM:<user at mydomain.com>
   > 250 2.1.0 Ok
   < RCPT TO:<some at recipient.com>
   > 250 2.1.5 Ok
   < BDAT 114098 LAST
   > 502 5.5.2 Error: command not recognized
   < Content-Type: multipart/alternative; 
boundary=Apple-Mail-55D35F74-2EB7-4B3B-A607-E421DD71C07A
   > 221 2.7.0 Error: I can break rules, too. Goodbye.


Apple Mail seems to ignore the fact that Postfix does not understand 
BDAT and Postfix does not like that :-)


 From a quick glance at the code it seems CHUNKING is always added to 
the capabilities and that's not configurable. Is this a bug or am I 
doing something wrong?


Thanks,

  Michael

Am 20.09.2018 um 11:04 schrieb Michael Goth:
> Hello,
> 
> I'm setting up Dovecot 2.3.2.1 as a submission proxy to a Postfix 
> backend server. Dovecot announces CHUNKING, but the Postfix backend does 
> not support (or announce) it.
> 
> HELO from Postfix:
> 
>  ? 220 backend.mydomain.com ESMTP Postfix (Ubuntu)
>  ? ehlo test
>  ? 250-backend.mydomain.com
>  ? 250-PIPELINING
>  ? 250-SIZE 104857600
>  ? 250-VRFY
>  ? 250-ETRN
>  ? 250-STARTTLS
>  ? 250-ENHANCEDSTATUSCODES
>  ? 250-8BITMIME
>  ? 250 DSN
> 
> 
> HELO from Dovecot proxy:
> 
>  ? 220 proxy.mydomain.com Dovecot ready.
>  ? ehlo test
>  ? 250-proxy.mydomain.com
>  ? 250-8BITMIME
>  ? 250-AUTH PLAIN LOGIN
>  ? 250-BURL imap
>  ? 250-CHUNKING
>  ? 250-ENHANCEDSTATUSCODES
>  ? 250-SIZE
>  ? 250-STARTTLS
>  ? 250 PIPELINING
> 
> 
> When a client sends BDAT, Postfix closes the connection. Here's a log 
> snippet from Postfix:
> 
>  ? < MAIL FROM:<user at mydomain.com>
>  ? > 250 2.1.0 Ok
>  ? < RCPT TO:<some at recipient.com>
>  ? > 250 2.1.5 Ok
>  ? < BDAT 114098 LAST
>  ? > 502 5.5.2 Error: command not recognized
>  ? < Content-Type: multipart/alternative; 
> boundary=Apple-Mail-55D35F74-2EB7-4B3B-A607-E421DD71C07A
>  ? > 221 2.7.0 Error: I can break rules, too. Goodbye.
> 
> 
> Apple Mail seems to ignore the fact that Postfix does not understand 
> BDAT and Postfix does not like that :-)
> 
> 
>  From a quick glance at the code it seems CHUNKING is always added to 
> the capabilities and that's not configurable. Is this a bug or am I 
> doing something wrong?
> 
> 
> Thanks,
> 
>  ?Michael
that "may" version depend

http://www.postfix.org/features.html
...
Postfix 3.4 	SMTP server support for RFC 3030 CHUNKING (without 
BINARYMIME).
...

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Aufsichtsratsvorsitzender: Florian Kirstein

On 09/20/2018 12:56 PM, Robert Schetterer wrote:
> Am 20.09.2018 um 11:04 schrieb Michael Goth:
>> Hello,
>>
>> I'm setting up Dovecot 2.3.2.1 as a submission proxy to a Postfix 
>> backend server. Dovecot announces CHUNKING, but the Postfix backend 
>> does not support (or announce) it.
>>
>> HELO from Postfix:
>>
>> ?? 220 backend.mydomain.com ESMTP Postfix (Ubuntu)
>> ?? ehlo test
>> ?? 250-backend.mydomain.com
>> ?? 250-PIPELINING
>> ?? 250-SIZE 104857600
>> ?? 250-VRFY
>> ?? 250-ETRN
>> ?? 250-STARTTLS
>> ?? 250-ENHANCEDSTATUSCODES
>> ?? 250-8BITMIME
>> ?? 250 DSN
>>
>>
>> HELO from Dovecot proxy:
>>
>> ?? 220 proxy.mydomain.com Dovecot ready.
>> ?? ehlo test
>> ?? 250-proxy.mydomain.com
>> ?? 250-8BITMIME
>> ?? 250-AUTH PLAIN LOGIN
>> ?? 250-BURL imap
>> ?? 250-CHUNKING
>> ?? 250-ENHANCEDSTATUSCODES
>> ?? 250-SIZE
>> ?? 250-STARTTLS
>> ?? 250 PIPELINING
>>
>>
>> When a client sends BDAT, Postfix closes the connection. Here's a
log
>> snippet from Postfix:
>>
>> ?? < MAIL FROM:<user at mydomain.com>
>> ?? > 250 2.1.0 Ok
>> ?? < RCPT TO:<some at recipient.com>
>> ?? > 250 2.1.5 Ok
>> ?? < BDAT 114098 LAST
>> ?? > 502 5.5.2 Error: command not recognized
>> ?? < Content-Type: multipart/alternative; 
>> boundary=Apple-Mail-55D35F74-2EB7-4B3B-A607-E421DD71C07A
>> ?? > 221 2.7.0 Error: I can break rules, too. Goodbye.
>>
>>
>> Apple Mail seems to ignore the fact that Postfix does not understand 
>> BDAT and Postfix does not like that :-)
>>
>>
>> ?From a quick glance at the code it seems CHUNKING is always added to 
>> the capabilities and that's not configurable. Is this a bug or am I
>> doing something wrong?
>>
>>
>> Thanks,
>>
>> ??Michael
> 
> that "may" version depend
> 
> http://www.postfix.org/features.html
> ...
> Postfix 3.4???? SMTP server support for RFC 3030 CHUNKING (without 
> BINARYMIME).
> ...
> 
As far as I understand, Dovecot always adds certain capabilities. This 
is the responsible code (I think):

https://github.com/dovecot/core/blob/c8d03c3cab68328947a5afb47f48aef5b5a1e4ab/src/submission/submission-client.c#L95