July 2019 - dovecot - dovecot.org

Replicate shared folders to warm standby host
by Axel Gluth 03 Jul '19

03 Jul '19

We like to set up our mail system in two datacenters but the wiki<https://wiki.dovecot.org/Replication> says "Shared folder replication doesn't work correctly..." I'm thinking about using an external loadbalancer to ensure that only one host will get connections. Normal operations: client ==imap=> loadbalancer ==imap=> host1 ==replication=> host2 Host1 or Datacenter1 is down: client ==imap=> loadbalancer ==imap=> host2 I see possible problems if host1 comes back and clients connect to host1 before the replication has caught up. But in our case that will be acceptable. Do you consider my idea as safe for production use? Has anybody real world experience with such a setup? Is there a better way to replicate shared folders? Thank you in advance for spending your time on thinking about my problem. Axel

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Dovecot/MSQL issue
by Nathan 03 Jul '19

03 Jul '19

Hello, I'm trying to work through an issue that cropped up on a server I've been working on and haven't found a very good workaround. Dovecot is operating in a jailed environment. The configuration in dovecot-sql.conf.ext has been set appropriately with the host=127.0.0.1 (which works from a jailed environment) and when dovecot attempts to auth it appears to perform a reverse dns lookup and overwrites the host with the result localhost before using the msql credentials 'user'@'localhost' which then fails after timing out. I'm currently running version 2.2.33.2 of dovecot. The workaround seems to be to have two credentials for the same user. 'user@'localhost' and 'user'@'127.0.0.1'; postfix operates in a jail as well and works around the jail issue in the same way but doesn't overwrite the specified host with a reverse dns lookup. Anyone have any suggestions on how to handle this issue better? or maybe there's a way to force different behavior which I haven't yet found in the documentation? Any help is much appreciated. Best Regards.

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dovecot.index.log: duplicate transaction log sequence (3)
by mabi 02 Jul '19

02 Jul '19

Hello, I am running Dovecot 2.3.5.1 on OpenBSD 6.5 with RainLoop as IMAP webmail client and just noticed the following error messages about duplicate transaction log sequences in the index log: Jul 01 13:15:58 Error: imap(<REMOVED_EMAIL1>)<21324><TVSmwJyMd0C5D+Vb>: Transaction log /var/vmail/<REMOVED_DOMAIN>/<REMOVED_EMAIL1>/dovecot.index.log: duplicate transaction log sequence (3) Jul 02 16:33:35 Error: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: Transaction log /var/vmail/<REMOVED_DOMAIN>/<REMOVED_EMAIL2>/dovecot.list.index.log: duplicate transaction log sequence (2) Jul 02 16:33:35 Panic: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: file mail-index-write.c: line 137 (mail_index_write): assertion failed: (file->hdr.prev_file_seq == hdr->log_file_seq) Jul 02 16:33:35 Fatal: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: master: service(imap): child 6812 killed with signal 6 (core not dumped - https://dovecot.org/bugreport.html#coredumps - set service imap { drop_priv_before_exec=yes }) Could this problem occur because I am using a Linux NFS server to store all the mails mounted under /var/mail ? Any hints what I can do to avoid these error messages? Thank you in advance. Best regards, Mabi

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Variable expansion with variables containing '%' (ldap with 2.3.6)
by Matthias Lay 02 Jul '19

02 Jul '19

Hi, there seems to be a problem when expanding variables containing a single '%' in value in dovecot V2.3.6 having a user defined Variable in user_attrs like user_attrs = name=home=/maildir/%Ln, =myvar=path/%L{ldap:sAMAccountName} and sAMAccountName conains a '%', in my example "sonder%zeichen" leads to: lda(sonder%zeichen)<5723><ov9uCHjOGV1bFgAACDoIoQ>: Fatal: Failed to expand plugin setting myvar = 'path/sonder%zeichen': Unknown variable '%z' same setup works with dovecot 2.2.29 Any Feedback appreciated. Thanks. Matze

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Variable expansion with variables containing '%' (ldap with 2.3.6)
by Matthias Lay 01 Jul '19

01 Jul '19

Hi, there seems to be a problem when expanding variables containing a single '%' in value in dovecot V2.3.6 having a user defined Variable in user_attrs like user_attrs = name=home=/maildir/%Ln, =myvar=path/%L{ldap:sAMAccountName} and sAMAccountName conains a '%', in my example "sonder%zeichen" leads to: lda(sonder%zeichen)<5723><ov9uCHjOGV1bFgAACDoIoQ>: Fatal: Failed to expand plugin setting myvar = 'path/sonder%zeichen': Unknown variable '%z' same setup works with dovecot 2.2.29 Any Feedback appreciated. Thanks. Matze

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