October 2021 - dovecot

Howto show user id for failed authentications attempts
by Jesús Ángel del Pozo 13 Oct '21

13 Oct '21

Hello, I am using dovecot_authenticator for Exim and I get a lot of authentication failure log entries, most of them due to brute force attacks. The log entries are like this: 2021-10-11 13:30:21 dovecot_login authenticator failed for ([5.188.206.194]) [5.188.206.194]: 535 Incorrect authentication data I wonder whether it would be possible to show the user ID the attacker used to authenticate himself. Here it is the SMTP data for one of these SMTP sessions: SMTP>> 250-disguised.domain.com Hello [5.188.206.194] [5.188.206.194] SMTP<< AUTH LOGIN SMTP>> 334 VXNlcm5hbWU6 received: CONT 1 UGFzc3dvcmQ6 SMTP>> 334 UGFzc3dvcmQ6 received: FAIL 1 user=webmaster(a)somedomain.net SMTP>> 535 Incorrect authentication data LOG: MAIN REJECT dovecot_login authenticator failed for ([5.188.206.194]) [5.188.206.194]: 535 Incorrect authentication data SMTP>> 421 disguised.domain.com lost input connection Warm regards, Jesús Ángel.

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stats events for use with prometheus
by Marc 12 Oct '21

12 Oct '21

I am struggling a bit with getting some basic metrics into prometheus. Is there some sample metrics file that has most common metrics configured? [@ conf.d]# cat 05-metrics.conf # https://doc.dovecot.org/admin_manual/event_design/#event-design metric imap_command { filter = event=imap_command_finished group_by = cmd_name tagged_reply_state }

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Containerize dovecot?
by MRob 12 Oct '21

12 Oct '21

Hello, anyone here has containerized dovecot? Can I ask general advice and experience please? are there any recommended articles/tutorial for containerize deploymnt and auto-scaling? Thank you.

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Dovecot-2.3.15 ignores imaps inet_listener
by David Favor 12 Oct '21

12 Oct '21

Processes that show up, only imap, no imaps... # service dovecot restart && netstat -pluten | egrep dovecot tcp 0 0 51.222.96.234:143 0.0.0.0:* LISTEN 0 3017752730 285711/dovecot Someone let me know what I've done wrong. Thanks! Changing conf.d/10-ssl.conf ssl=yes seems to have no effect, thus ssl=no shows up in the config, so maybe that's the problem. Data follows... _______ # dovecot -n -c /etc/dovecot/dovecot.conf # 2.3.15 (0503334ab1): /etc/dovecot/dovecot.conf # OS: Linux 5.4.0-56-generic x86_64 Ubuntu 20.04.3 LTS # Hostname: net15-david-favor-mail mail_location = mbox:~/mail:INBOX=/var/mail/%u namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } protocols = " imap lmtp" service imap-login { inet_listener imap { address = 51.222.96.234 port = 143 } inet_listener imaps { address = 51.222.96.234 port = 993 ssl = yes } } ssl = no userdb { driver = passwd }

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two different mail_location
by Gabx 12 Oct '21

12 Oct '21

Hi everybody, my mail system has all users in usual path ~ . Only one user is in /var/%u . This user doesn't receive emails. I guess it is because its $HOME is on a different path than the one specified in dovecot mail_location which is: > mail_location = maildir:~/%u/Maildir What's the best way to solve this issue ? Namespaces ? If so could someone explain me how ? Best Regards Gabriel -- GPG fingerprint: 5A6A F742 ACEA C9A7 93A8 8D5E 7AEF 5A02 D080 89F7 Contact: xmpp://gabx@jabber.tcpreset.net

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Dovecot Replica one user at a time
by Claudio Corvino 12 Oct '21

12 Oct '21

Hi all, I have two IMAP/LMTP Dovecot server in replica (version 2.3.4.1) for testing purposes, both connected through an IPsec tunnel, I use LDAP/AD for /userdb, /all seems to work fine. Now I would like to go in production where at the moment I have only one server active and setup the replica too ... but! I need to know how I can exclude all the users from replication (help/examples appreciated!) and doing replication one user at a time, in order to not saturate bandwidth on the IPsec tunnel. I read https://wiki.dovecot.org/Replication: "Since v2.3.1 you can disable replication for a user by providing 'noreplicate' user database field <https://wiki.dovecot.org/UserDatabase/ExtraFields>. Another way to disable replication for some users is to return mail_replica field from userdb for users you want to replicate." but I can't figure out how to do it. One last question: since I have to deal with huge mailboxes, if prior to activate replication I do an rsync between the two Dovecot filesystems, does the replication will work? Thanks in advance! Cheers -- *Claudio Corvino IT Systems Administrator*

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Authentication problems due to file ownership issue.
by C. Petro 12 Oct '21

12 Oct '21

I am getting: Oct 03 20:19:52 auth: Error: net_connect_unix(auth-worker) in directory /run/dovecot failed: Permission denied (euid=5000(vmail) egid=5000(vmail) missing +r perm: /run/dovecot/auth-worker, dir owned by 0:0 mode=0755) Because: root@mailserver:/run/dovecot# ls -l auth-worker srw------- 1 dovecot root 0 Oct 3 20:09 auth-worker When it really needs to be "vmail" (I think). I have set: service auth-worker { # Auth worker process is run as root by default, so that it can access # /etc/shadow. If this isn't necessary, the user should be changed to # $default_internal_user. user = vmail group = vmail } in 10-master.conf (because I'm using postfixadmin/mariadb to store user information, I don't *want* access to /etc/shadow) I set this about an hour ago, then applied some security patches and restarted (ubuntu 20.04 system) and it didn't change. I then manually did a "chown vmail: of that file, and I got further. I had a different problem that I resolved, and then restarted dovecot, and /run/dovecot/auth-worker reverted. I'm not sure where I need to set this. Thanks. Petro. :wq

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haproxy config manual update for multiple ports
by Marc 09 Oct '21

09 Oct '21

https://wiki2.dovecot.org/HAProxy Maybe update this to having multiple ports (if this is even possible) frontend ft_imap bind :110 << bind :143 mode tcp default_backend bk_imap backend bk_imap mode tcp balance leastconn stick store-request src stick-table type ip size 200k expire 30m server s1 backend.example.com:10143 send-proxy-v2 <<< how to put more ports here?

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SNI via lookup?
by Felipe Gasper 08 Oct '21

08 Oct '21

Hello, How (if at all) might I configure a Dovecot server to read its SNI configuration dynamically? Right now I’ve got thousands of domains all served from a quite-large static config file that has to be rebuilt every time a domain is added or removed. It would be much simpler if there were a way to make Dovecot call out to some external service to fetch a given domain’s certificate. Thank you in advance! cheers, -Felipe Gasper

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writing Maildir subscriptions file outside of dovecot
by David Mandelberg 08 Oct '21

08 Oct '21

Hi, Is it safe to write to the Maildir subscriptions file directly? I'm trying to figure out a way to make sure the subscriptions match the actual folders exactly. I know how to subscribe to existing mailboxes with `doveadm mailbox list` and `doveadm mailbox subscribe`, but the latter seems to only accept mailboxes on the command line, and any local user can see the command line of any other user's commands. Also, that doesn't handle unsubscribing from non-existent mailboxes. I think unsubscribing from any mailboxes listed in `doveadm mailbox list -s` but not in `doveadm mailbox list` would work, but it has the same issue of mailboxes on the command line. It looks like I could do what I want with something like this command, but I'm not sure if it's safe to write directly to the subscriptions file: { echo INBOX; ls -1A | grep '^\.' | cut -c 2-; } > subscriptions (I was also thinking about using `doveadm mailbox list` to write the subscriptions file directly, but it looks like they use different separators and encodings.)

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