October 2021 - dovecot

logging for doveadm replicator?
by Norman King 23 Oct '21

23 Oct '21

Hi. We have a doveadm replicator config set up to do 2 way sync of all users on our mail server. Currently running doveadm replicator status gives the following. ``` root@mail:~# doveadm replicator status Queued 'sync' requests 0 Queued 'high' requests 0 Queued 'low' requests 1 Queued 'failed' requests 0 Queued 'full resync' requests 677 Waiting 'failed' requests 4 Total number of known users 1577 ``` Is there anything i can do to get these full resyncs to happen faster? doveadm replicator dsync-status routinely shows most of the slots as not connected. Where can i start to either see logs of the replicator plugin to see if i can diagnose why it's so far behind? or is there a way to force these syncs to happen faster? Thanks. -- regards Norman King Compass Foundation sysadmin/tech support Phone, 856-974-5335 ext 221 support(a)compassfoundation.io Website <https://compassfoundation.io>

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action based on IMAP ID fields
by Jörg Backschues 22 Oct '21

22 Oct '21

Hello, is it possible based on the information we get from the IMAP ID fields sent by a client to start some actions e.g. reject an IMAP client with a certain OS version? -- Kind Regards Jörg Backschues

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Create a separated mailbox for archived mails
by Claudio Corvino 22 Oct '21

22 Oct '21

Hi, I have an MTA configured with Postfix that deliver email to an IMAP/LMTP Dovecot server version 2.3.4.1 configured to bind LDAP/AD for users. I would like to configure Dovecot to create another mailbox to archive mails of users to a separated NFS mount. Here is my /dovecot-ldap.conf/: [...] /ldap_version=3// //auth_bind = yes// //dn = XXX// //dnpass = XXX// //scope = subtree// //user_attrs = sAMAccountName=home=/mnt/mail-storage-dev/%$,=uid=501,=gid=501// //pass_attrs = sAMAccountName=user// //user_filter = (&(objectclass=person)(samaccountname=%n))// //pass_filter= (&(objectclass=person)(samaccountname=%n))/ [...] I think I will add another conf file, let's say /dovecot-ldap-archive.conf /using "url" as LDAP/AD filed to distinguish from normal users: [...] /ldap_version=3// //auth_bind = yes// //dn = XXX// //dnpass = XXX// //scope = subtree// //user_attrs = url=home=/mnt/mail-storage-archive/%$,=uid=501,=gid=501// //pass_attrs = url=user// //user_filter = (&(objectclass=person)(url=%n))// //pass_filter= (&(objectclass=person)(url=%n))/ [...] I then added to "test" user a "url" filed into Active Directory named /test-archive//, b/ut it's not working, when I bind Dovecot with: /doveadm user test-archive/ I receive: /field value// //userdb lookup: user test-archive doesn't exist/ With test user it works: /doveadm user test// //field value// //uid 501// //gid 501// //home /mnt/mail-storage-dev/test// //mail maildir:~/Maildir:INDEX=/var/indexes/test/ What I'm doing wrong? Thanks in advance! // -- *Claudio Corvino IT Systems Administrator*

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local_name in dovecot for SNI and wildcard
by Alessio Cecchi 20 Oct '21

20 Oct '21

Hi, in dovecot configuration the options "local_name" can support wildcard domain name (es. *.mailserver.com)? This because we have a wildcard SSL certificate and I prefer to specifica a wildcard name instead of single. Is fine this? local_name *.mailserver.com { ssl_cert = </etc/dovecot/ssl/mailserver.com.pem ssl_key = </etc/dovecot/ssl/mailserver.com.key } And local_name can support multiple hostname in the same line? local_name pop.mailserver.com imap.mailserver.com { ssl_cert = </etc/dovecot/ssl/mailserver.com.pem ssl_key = </etc/dovecot/ssl/mailserver.com.key } Thanks -- Alessio Cecchi Postmaster @ http://www.qboxmail.it https://www.linkedin.com/in/alessice

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dovecot-lda -> lmtp server ?
by Scott Q. 17 Oct '21

17 Oct '21

I'm stuck with using Qmail which has no LMTP support, and thus I'm using dovecot-lda which has certain drawbacks. Has anyone found a way to direct dovecot-lda to deliver the mail to the LMTP server or any other way for Qmail to deliver the mail to the LMTP server directly ? Thanks!

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Broken uidlist when using NFS on newer kernels
by Jeremy Hanmer 14 Oct '21

14 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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