- dovecot - dovecot.org

Broken uidlist when using NFS on newer kernels
by Jeremy Hanmer 15 Oct '21

15 Oct '21

I know this has been reported in the past, but I think I have some useful new information on the problem. After an OS upgrade from Ubuntu Xenial (4.4.0 kernel) to Ubuntu Focal (5.4.0 kernel) and corresponding upgrade from Dovecot 2.2.27 to 2.3.7.2, we've started seeing broken uidlist files to an extent that's making larger mail boxes nearly unusable because the file is constantly being regenerated. I've also used the 2.3.16-2+ubuntu20.04 version distributed from dovecot.org and the behavior is unchanged. The environment consists of NFS mounts from a NetApp device, with a couple dozen MX servers receiving mail and about a hundred IMAP/POP servers. This is the exact error (note the blank after "invalid data"): Error: Mailbox INBOX: Broken file /mnt/morty/morty2/gravest/x15775549/Maildir/dovecot-uidlist line 373: Invalid data: I've been able to trigger the problem rather easily by piping an email to dovecot-lda in a loop and reading the resulting dovecot-uidlist file on a different server. What it shows is that occasionally we're seeing the last line of the file prepended with a number of null bytes equal to the line that's being written (for example, if the entry is "35322 :1633719038.M516419P3623238.pdx1-sub0-mail-mx202,S=2777,W=2832", we'll have it prepended by 69 null bytes). This then breaks the IMAP process' ability to read the file. My first thought was to extend the retry functionality so the imap proces makes more attempts to read the file when it detects a problem like this, but would love input from someone more familiar with the codebase.

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email migration of mdbox to sdbox with set index in mail_location
by filipe＠digirati.com.br 13 Oct '21

13 Oct '21

Hello, my name is Filipe I'm migrating an email server to another new server. Accounts have their storage configured as mdbox and their index being saved in another storage device. I want to migrate all messages to the new server with a new storage mode, sdbox. The new server will have storage settings set to sdbox for email accounts: In dovecot's doc it says mdbox mode is the only one that supports index storage on another device. https://doc.dovecot.org/admin_manual/mailbox_formats/dbox/#layout /"Index files can be stored in a different location by using the INDEX parameter in the mail location specification. If the INDEX parameter is specified, it will override the root mail location for index files and the "map index" file (mdbox only). "/ Even with this warning I performed the migration of some accounts as a test. running the commands from server A to server B. "Server A" conf: dovecot version: 2.2.33.2 /mail_location: mdbox:/var/spool/imap/test=x.com:INDEX=/var/lib/imap/user/test=x.com/ "Server B" conf: dovecot version: 2.3.7.2 /mail_location: sdbox:/var/spool/imap/test=x.com:INDEX=/var/lib/imap/user/test=x.com/ command executed on server A to execute message migration: /root@serverA: ~# doveadm sync -u test=x.com ssh root@*serverB* doveadm dsync-server -u test=x.com/ In the end, the message migration was successful and the access to the email account worked normally on server B. The question is whether dovecot has this support to move the index when I use the sdbox? Thank you for your help

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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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