dovecot-submission SMTP send error with Thunderbird (BODY=8BITMIME)

[Stephan Bosch]

Op 12/23/2017 om 7:18 AM schreef Reuben Farrelly:
> Hi,
>
> With latest 2.3 -git (and 2.3.0 release), I'm running into this error
> with Thunderbird:
>
> "An error occurred while sending mail. The mail server responded:
> 5.5.4 Unsupported mail BODY type. Please verify that your email
> address is correct in your account settings and try again."
>
> This is fatal and means Thunderbird cannot use the submission service
> - fortunately I can revert back to a native Postfix service which works.
>
> Here's a tcpdump of the conversation:
>
> thunderstorm /etc/dovecot/conf.d # tcpdump -A port 587
>
> dropped privs to tcpdump
> tcpdump: verbose output suppressed, use -v or -vv for full protocol
> decode
> listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes

I cannot reproduce this behavior so far.

(ngrep -Wbyline produces more readable output)

> Curiously enabling rawlog doesn't capture this error, which is why I
> used tcpdump above.  The logs from it like this:
>
> thunderstorm /run/dovecot/rawlogs # cat 20171219-141149.5633.1.in
> 1513653109.109030 220 thunderstorm.reub.net ESMTP Postfix (3.3-20171028)
> 1513653109.109266 250-thunderstorm.reub.net
> 1513653109.109266 250-PIPELINING
> 1513653109.109266 250-SIZE 40960000
> 1513653109.109266 250-VRFY
> 1513653109.109266 250-ETRN
> 1513653109.109266 250-STARTTLS
> 1513653109.109266 250-ENHANCEDSTATUSCODES
> 1513653109.109266 250-8BITMIME
> 1513653109.109266 250-DSN
> 1513653109.109266 250 SMTPUTF8
> 1513653130.973720 221 2.0.0 Bye
>
> thunderstorm /run/dovecot/rawlogs # cat 20171219-141149.5633.1.out
> 1513653109.109087 EHLO thunderstorm.reub.net
> 1513653130.973351 QUIT
> 1513653130.973829 QUIT
> thunderstorm /run/dovecot/rawlogs #

Double QUIT. That is a minor bug, but not related.

>
> This with:
>
> # Write protocol logs for relay connection to this directory for
> debugging
> #submission_relay_rawlog_dir =
> submission_relay_rawlog_dir = /run/dovecot/rawlogs/
>
> Is this a separate but unrelated problem with rawlog support in this
> the submission?  I would have expected it to capture the full
> conversation log including any protocol errors and failures like this.

No. This is the connection with the relay (backend MTA) server. Use the
normal Dovecot rawlog facilities to capture protocol interaction with
the client instead.

Well, now we do know for sure that Dovecot is responsible for the error,
since the interaction with the relay server shows no issues.

I will continue experimenting a bit. I still have to actually try this
with Thunderbird. Any other configuration I should know about (`dovecot
-n`)?

Regards,

Stephan.