Dovecot 2.4 bug with Thunderbird

[Panormitis]

DirectAdmin Developers
Please see:

Thunderbird and Dovecot 2.4.0 Incompatibility - dovecot - dovecot.org

dovecot.org

1968384 - BAD Error in IMAP command APPEND: Missing ')'

RESOLVED (nobody) in MailNews Core - Networking: IMAP. Last updated 2025-05-27.

bugzilla.mozilla.org

I'm using Thunderbird and I think I'm experiencing that bug. Once I set mail.imap.use_literal_plus to false, in Thunderbird, everything works normally.

Since the fix is already included: https://github.com/dovecot/core/com...12df6e0eed634aa4fe92c225b54ef5ee965b35c.patch
I believe Dovecot should be recompiled using the latest source files.

 

[Panormitis]

It seems my issue was different. I'm using Thunderbird and from time to time I wasn't receiving mail at startup nor I could save mail to Sent of imap accounts. Most times I could restart Thunderbird and the issue was going away for a while until it resurface randomly again. However all these started occurring when I upgraded to Dovecot 2.4, so I was primarily suspecting Dovecot, not Thunderbird.
So I investigated further:

In /var/log/dovecot-lmtp-errors.log there were some erros such as: "lmtp(4085101): Error: conn unix:/run/dovecot/anvil (pid=3904345,uid=0): net_connect_unix(/run/dovecot/anvil) failed: Permission denied".
lmtp runs as mail:mail but /run/dovecot/anvil had root:root ownership.

So I did the following:

cd /usr/local/directadmin/custombuild
mkdir -p custom/dovecot/2.4/conf
cp configure/dovecot/2.4/conf/service.conf custom/dovecot/2.4/conf
cd custom/dovecot/2.4/conf

Edit service.conf and add:
service anvil {
  unix_listener anvil {
    group = mail
    mode = 0660
  }
}

Then, execute:
da build dovecot_conf
systemctl restart dovecot

/run/dovecot/anvil should have root:mail ownership now. Permission denied errors are gone and Thunderbird seems to behave correctly.

 

[Richard G]

lmtp runs as mail:mail but /run/dovecot/anvil had root:root ownership.

Oeps... seems this is indeed wrongly done. I got the same errors in my log:

Error: conn unix:/run/dovecot/anvil (pid=961,uid=0): net_connect_unix(/run/dovecot/anvil) failed: Permission denied

Unfortunately I don't have an older server running older Dovecot to see what permissions were before.

However, how do you know lmtp is running as mail?
In my case it's running as user or as root.

root       69857  0.0  0.0  16332 11264 ?        S    00:52   0:00  \_ dovecot/lmtp
startva+  123901  0.0  0.0  22404 15232 ?        S    01:05   0:00  \_ dovecot/lmtp [local READY]

However, the lmtp.conf says mail.

# LMTP socket for local delivery from exim
service lmtp {
  executable = lmtp -L
  process_min_avail = 16
  unix_listener lmtp {
    user = mail
    group = mail
    mode = 0660
  }
}

Is that something DA needs fixing @fln?