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

[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


14:12:19.975982 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [S], seq 572328223, win 64800, 
options [mss 1440,nop,wscale 8,nop,nop,sackOK], length 0
`._.. .? .D.1...E.....>. .D.1..........#...K".  ........ .w..............
14:12:19.976022 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [S.], seq 
3954361671, ack 572328224, win 28800, options [mss 
1440,nop,nop,sackOK,nop,wscale 7], length 0
`.c|. .@ .D.1..........# .D.1...E.....>..K.....G". ..p.:4..............
14:12:19.976158 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [.], ack 1, win 8235, length 0
`._....? .D.1...E.....>. .D.1..........#...K".   ...HP. +. ..
14:12:19.983409 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [P.], seq 1:43, ack 
1, win 225, length 42
`.c|.>.@ .D.1..........# .D.1...E.....>..K.....H".       P...:R..220 
thunderstorm.reub.net Dovecot ready.

14:12:19.992790 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [P.], seq 1:54, ack 43, win 8234, 
length 53
`._..I.? .D.1...E.....>. .D.1..........#...K".   ...rP. *.H..EHLO 
[IPv6:2001:44b8:31d4:1311:45ec:e191:8093:3e9d]

14:12:19.992828 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [.], ack 54, win 
225, length 0
`.c|...@ .D.1..........# .D.1...E.....>..K.....r".      UP...:(..
14:12:19.993027 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [P.], seq 43:200, 
ack 54, win 225, length 157
`.c|...@ .D.1..........# .D.1...E.....>..K.....r". 
UP...:...250-thunderstorm.reub.net
250-8BITMIME
250-AUTH PLAIN LOGIN
250-BURL imap
250-CHUNKING
250-ENHANCEDSTATUSCODES
250-SIZE
250-STARTTLS
250 PIPELINING

14:12:20.015953 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [P.], seq 54:91, ack 200, win 
8234, length 37
`._..9.? .D.1...E.....>. .D.1..........#...K".  U....P. *....AUTH PLAIN xxxx

14:12:20.035676 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [P.], seq 200:222, 
ack 91, win 225, length 22
`.c|.*.@ .D.1..........# .D.1...E.....>..K......".      zP...:>..235 
2.7.0 Logged in.

14:12:20.036642 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [P.], seq 91:143, ack 222, win 
8234, length 52
`._..H.? .D.1...E.....>. .D.1..........#...K".  z...%P. *....MAIL 
FROM:<xxx at reub.net> BODY=8BITMIME SIZE=444

14:12:20.036826 IP6 inside-mail.reub.net.submission > 
2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175: Flags [P.], seq 222:260, 
ack 143, win 225, length 38
`.c|.:.@ .D.1..........# .D.1...E.....>..K.....%".      .P...:N..555 
5.5.4 Unsupported mail BODY type

14:12:20.089196 IP6 2001:44b8:31d4:1311:45ec:e191:8093:3e9d.61175 > 
inside-mail.reub.net.submission: Flags [.], ack 260, win 8233, length 0
`._....? .D.1...E.....>. .D.1..........#...K".  ....KP. )....


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 #

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.

Reuben