January 2026 - dovecot

IMAP with Dovecot: Kerberos/GSSAPI in LAN only
by r.barclay＠habmalnefrage.de 19 Jan '26

19 Jan '26

Hi, I'm setting up a new IMAPS server using Dovecot 2.4 at the moment. I'd like my network internal users to authenticate using GSSAPI. The server is also exposed to the Internet for smart phone email access. I want to offer PLAIN login only for external users as they can't be legitimate internal Kerberos users. (Just as an additional layer of security.) Would this approach work? service imap-login { inet_listener imaps_external { port = 1993 ssl = yes auth_mechanisms = plain login } inet_listener imaps_internal { port = 7993 ssl = yes auth_mechanisms = plain login gssapi } } Then I'd allow only port 1993 externally and keep port 7993 for the LAN. Thank you for your advice! Reg

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2.4.2 breaks big-endian builds
by Noah Meyerhans 19 Jan '26

19 Jan '26

From the Debian s390 build log, no merging parent is NULL ............................................ : ok no merging parent sent to stats ...................................... : ok no merging parent timestamp differs .................................. : ok merge events parent NULL ............................................. : ok merge events parent sent to stats .................................... : ok skip empty parents ................................................... : ok merge events and skip empty parents .................................. : ok parent updated after send ............................................ : ok large event id ....................................................... : ok merge events global .................................................. : ok 0 / 10 tests failed test-master-service-settings.c:472: Assert(#16) failed: strstr(error, tests[i].error) != NULL test-master-service-settings: Error: Failed to parse configuration: Settings block doesn't end with NUL at offset 70 test-master-service-settings.c:472: Assert(#19) failed: strstr(error, tests[i].error) != NULL test-master-service-settings: Error: Failed to parse configuration: Settings block doesn't end with NUL at offset 84 master_service_settings_read() - binary corruption ................... : FAILED 1 / 1 tests failed make[4]: *** [Makefile:958: check-local] Error 1 make[4]: Leaving directory '/build/reproducible-path/dovecot-2.4.2+dfsg1/src/lib-master' make[3]: *** [Makefile:806: check-am] Error 2 make[3]: Leaving directory '/build/reproducible-path/dovecot-2.4.2+dfsg1/src/lib-master' make[2]: *** [Makefile:604: check-recursive] Error 1 make[2]: Leaving directory '/build/reproducible-path/dovecot-2.4.2+dfsg1/src' make[1]: *** [Makefile:739: check-recursive] Error 1 make[1]: Leaving directory '/build/reproducible-path/dovecot-2.4.2+dfsg1' The build failure was introduced with commit 41bd7a502 ("lib-settings, config: Use native CPU endianess in binary config file"). The build is successful at the previous commit, but fails at that commit. I haven't yet determined whether the failure is with the code itself or the test. Full build log is available at https://buildd.debian.org/status/fetch.php?pkg=dovecot&arch=s390x&ver=1%3A2… noah

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Re: Issue upgrading from 2.3.x to 2.4.1 when changing the mail driver from mbox to dbox
by Michael Slusarz 18 Jan '26

18 Jan '26

> On 01/16/2026 10:50 AM MST actionmystique via dovecot <dovecot(a)dovecot.org> wrote: > > I followed all the requirements detailed in https://doc.dovecot.org/main/installation/upgrade/2.3-to-2.4.html, but there seems to be an issue on my side configuring correctly the Mailbox locations. > In 10-mail.conf, I changed the mail driver from: > mail_driver = mbox --> mail_driver = dbox > I thought that would be sufficient but apparently, it is not the case. Changing mailbox format requires migration. See https://doc.dovecot.org/latest/core/admin/migration.html michael > All updated configurations are: > dovecot -n > # 2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf > # Pigeonhole version 2.4.1-4 (0a86619f) > # OS: Linux 6.17.0-8-generic x86_64 Ubuntu 25.10 > # Hostname: <hostname> > dovecot_config_version = 2.4.1 > auth_debug = yes > auth_debug_passwords = yes > auth_mechanisms = plain > auth_verbose = yes > auth_verbose_passwords = sha1 > dovecot_storage_version = 2.4.1 > fts_autoindex = yes > fts_autoindex_max_recent_msgs = 999 > fts_search_add_missing = yes > log_debug = category=ssl > log_timestamp = "%Y-%m-%d %H:%M:%S " > mail_driver = dbox > mail_home = /home/%{user|username} > mail_inbox_path = /var/mail/%{user} > mail_path = %{home}/mail > mail_privileged_group = mail > protocols = imap lmtp > ssl = required > ssl_cipher_list = <some list> > ssl_curve_list = <some list> > ssl_min_protocol = TLSv1.3 > passdb pam { > driver = pam > fields { > allow_nets = <nets> > } > result_failure = return-fail > result_internalfail = return-fail > result_success = return-ok > skip = never > } > userdb passwd { > } > namespace inbox { > inbox = yes > mailbox Drafts { > special_use = "\\Drafts" > } > mailbox Junk { > special_use = "\\Junk" > } > mailbox Trash { > special_use = "\\Trash" > } > mailbox Sent { > special_use = "\\Sent" > } > mailbox virtual/All { > special_use = "\\All" > } > } > service imap-login { > inet_listener imap { > port = 143 > listen = 127.0.0.1 [::1] > } > inet_listener imaps { > port = 993 > ssl = yes > listen = * [::] > } > } > service pop3-login { > inet_listener pop3 { > } > inet_listener pop3s { > } > } > service submission-login { > inet_listener submission { > } > } > service lmtp { > inet_listener lmtp { > port = 8024 > listen = 127.0.0.1 ::1 > } > } > service imap { > } > service pop3 { > } > service submission { > } > service auth { > unix_listener auth-userdb { > } > unix_listener /var/spool/postfix/private/auth { > group = postfix > mode = 0660 > user = postfix > } > } > service auth-worker { > } > service dict { > unix_listener dict { > } > } > ssl_server { > ca_file = <path> > cert_file = <path> > key_file = <path> > prefer_ciphers = server > request_client_cert = yes > require_crl = no > } > ssl_client { > ca_dir = /etc/ssl/certs > require_valid_cert = yes > } > protocol lmtp { > auth_username_format = %{user | username} > mail_plugins = quota sieve > postmaster_address = <email> > } > > In mail.err, I get multiple error messages such as: > Error: Mailbox INBOX: open() failed with file /var/mail/<user>/dovecot.index.log: Not a directory > of course, because /var/mail/<user> is not a folder but a file containing all the received mails. > > So, in /var/mail, I have one file per user, plus one user.lock.sav, and also some weird files such as mu8xTBeL, muaBkJQL... belonging to one of the user. > > How should I configure dbox? > _______________________________________________ > dovecot mailing list -- dovecot(a)dovecot.org > To unsubscribe send an email to dovecot-leave(a)dovecot.org

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Issue upgrading from 2.3.x to 2.4.1 when changing the mail driver from mbox to dbox
by actionmystique＠gmail.com 16 Jan '26

16 Jan '26

I followed all the requirements detailed in https://doc.dovecot.org/main/installation/upgrade/2.3-to-2.4.html, but there seems to be an issue on my side configuring correctly the Mailbox locations. In 10-mail.conf, I changed the mail driver from: mail_driver = mbox --> mail_driver = dbox I thought that would be sufficient but apparently, it is not the case. All updated configurations are: dovecot -n # 2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.1-4 (0a86619f) # OS: Linux 6.17.0-8-generic x86_64 Ubuntu 25.10 # Hostname: <hostname> dovecot_config_version = 2.4.1 auth_debug = yes auth_debug_passwords = yes auth_mechanisms = plain auth_verbose = yes auth_verbose_passwords = sha1 dovecot_storage_version = 2.4.1 fts_autoindex = yes fts_autoindex_max_recent_msgs = 999 fts_search_add_missing = yes log_debug = category=ssl log_timestamp = "%Y-%m-%d %H:%M:%S " mail_driver = dbox mail_home = /home/%{user|username} mail_inbox_path = /var/mail/%{user} mail_path = %{home}/mail mail_privileged_group = mail protocols = imap lmtp ssl = required ssl_cipher_list = <some list> ssl_curve_list = <some list> ssl_min_protocol = TLSv1.3 passdb pam { driver = pam fields { allow_nets = <nets> } result_failure = return-fail result_internalfail = return-fail result_success = return-ok skip = never } userdb passwd { } namespace inbox { inbox = yes mailbox Drafts { special_use = "\\Drafts" } mailbox Junk { special_use = "\\Junk" } mailbox Trash { special_use = "\\Trash" } mailbox Sent { special_use = "\\Sent" } mailbox virtual/All { special_use = "\\All" } } service imap-login { inet_listener imap { port = 143 listen = 127.0.0.1 [::1] } inet_listener imaps { port = 993 ssl = yes listen = * [::] } } service pop3-login { inet_listener pop3 { } inet_listener pop3s { } } service submission-login { inet_listener submission { } } service lmtp { inet_listener lmtp { port = 8024 listen = 127.0.0.1 ::1 } } service imap { } service pop3 { } service submission { } service auth { unix_listener auth-userdb { } unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } } service auth-worker { } service dict { unix_listener dict { } } ssl_server { ca_file = <path> cert_file = <path> key_file = <path> prefer_ciphers = server request_client_cert = yes require_crl = no } ssl_client { ca_dir = /etc/ssl/certs require_valid_cert = yes } protocol lmtp { auth_username_format = %{user | username} mail_plugins = quota sieve postmaster_address = <email> } In mail.err, I get multiple error messages such as: Error: Mailbox INBOX: open() failed with file /var/mail/<user>/dovecot.index.log: Not a directory of course, because /var/mail/<user> is not a folder but a file containing all the received mails. So, in /var/mail, I have one file per user, plus one user.lock.sav, and also some weird files such as mu8xTBeL, muaBkJQL... belonging to one of the user. How should I configure dbox?

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Is dovecot CE 2.4.x supported with 32bit compile?
by dovecot＠freakout.de 16 Jan '26

16 Jan '26

these compiler messages make me nervous: test-event-filter.c:1006:53: warning: integer overflow in expression of type 'long int' results in '-694967296' [-Woverflow] 1006 | { "field = 1hours", 60L * 60 * 1000 * 1000, TRUE },

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Blocking with RBLs
by Lefteris Tsintjelis 15 Jan '26

15 Jan '26

Hi, Is there a way to block with RBLs? I already have a really good and very trustworthy and accurate internal one that works extremely well and fast with my SMTP servers for years now. Is there a way to apply the same RBL to dovecot? Logs are really going crazy as they stopped with SMTP and started with IMAP for a while now since dovecot is wide open to these attacks. Anvil does not seem to do much here. I am looking for solutions other than fail2ban or anything similar to this. Lefteris

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issue with quota warning using separate namespace quotas
by Andreas Oster 15 Jan '26

15 Jan '26

Hello everyone, I am currently trying to implement quota warnings for two separate namespaces (INBOX, MailArchive). The individual quota values for these namespaces are derived from ldap, which is working fine. However since adding the quota_warning configuration error messages appear in the logs: Error: quota-count: Filter quota_warning=warn-95 unexpectedly not found (invalid userdb or -o override settings?) Error: quota-count: Filter quota_warning=ma-warn-95 unexpectedly not found (invalid userdb or -o override settings?) The relevant configuration parameters from my config: quota_storage_size = 1G userdb ldap { fields { quota/ma_quota/storage_size = %{ldap:quota1} quota_storage_size = %{ldap:quota2} } } namespace subscriptions { mailbox_subscriptions_filename = subscriptions hidden = yes list = no prefix = subscriptions = yes } namespace inbox { inbox = yes prefix = INBOX/ subscriptions = no quota user_quota { name = User Quota quota_warning warn-95 { quota_storage_percentage = 95 execute quota-warning { args = 95 %{user} } } quota_warning warn-80 { quota_storage_percentage = 80 execute quota-warning { args = 80 %{user} } } quota_warning warn-under { quota_storage_percentage = 100 threshold = under execute quota-warning { args = below %{user} } } } mailbox Drafts { auto = subscribe special_use = "\\Drafts" } mailbox Sent { auto = subscribe special_use = "\\Sent" } mailbox "Sent Messages" { special_use = "\\Sent" } mailbox Spam { auto = subscribe special_use = "\\Junk" } mailbox Junk { special_use = "\\Junk" } mailbox Trash { auto = subscribe special_use = "\\Trash" quota_storage_percentage = 110 } } namespace MailArchive { mail_driver = maildir mail_index_path = /var/mail/indexes/mailarchive/%{user} mail_path = /var/mail/mailarchive/%{user}/Maildir list = children prefix = MailArchiv/ subscriptions = no type = private quota ma_quota { name = MailArchive Quota quota_warning ma-warn-95 { quota_storage_percentage = 95 execute quota-warning { args = 95 %{user} } } quota_warning ma-warn-80 { quota_storage_percentage = 80 execute quota-warning { args = 80 %{user} } } quota_warning ma-warn-under { quota_storage_percentage = 100 threshold = under execute quota-warning { args = below %{user} } } } mailbox "Archived Mails" { auto = subscribe special_use = "\\Archive" } } } service quota-warning { executable = script /var/mail/scripts/quota-warning.sh user = vmail unix_listener quota-warning { } } Does anyone have an idea what could be causing this behavior ? Thank you very much for your kind help. Andreas

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Panic in logs
by Kamil Jońca 13 Jan '26

13 Jan '26

Recently I found in my lda logs: 2025-12-30T07:55:14.717927+01:00 alfa dovecot: lda(kjonca): Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 i_syslog_fatal_handler[0x7f99a2351430] -> #3 i_panic[0x7f99a226d453] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 buffer_append[0x7f99a2345270] -> #8 dregex_code_match_groups[0x7f99a233f1a0] -> #9 [unw_get_proc_name() failed: -10] -> #10 [unw_get_proc_name() failed: -10] -> #11 sieve_match_value[0x7f99a117f770] -> #12 sieve_match[0x7f99a117fa30] -> #13 [unw_get_proc_name() failed: -10] -> #14 sieve_interpreter_continue[0x7f99a117e100] -> #15 sieve_multiscript_run[0x7f99a1190330] -> #16 [unw_get_proc_name() failed: -10] -> #17 mail_deliver[0x7f99a27e54a0] -> #18 main[0x55e371c555e0] -> #19 __libc_start_call_main[0x7f99a1e29f00] -> #20 __libc_start_main_alias_2[0x7f99a1e29fa0] -> #21 _start[0x55e371c566a0] And sadly it seems, that mail is missing (it was passed to pipe program to further processing) KJ -- http://wolnelektury.pl/wesprzyj/teraz/ When you go out to buy, don't show your silver.

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Dovecot 2.4.2: How to fix maildir incoming mails going to cur/ instead of new/
by Andy Baugh 13 Jan '26

13 Jan '26

Add the following to dovecot.conf if you use maildir: # Disable the maildir breaking default behavior of # mail_attachment_detection_options, as setting ANY flag forces you out of new/ # and into cur/ mail_attachment_detection_options = ..and voila, maildir works as it previously did. This is *hinted* to in the migration guide document, as the old default value was shown as blank in the table, but I didn't figure it out till reading through the source code to find what was adding the 'a' flag to all incoming mails (thus forcing them out of new, as any flag does this). Cheers, -- Thomas "Andy" Baugh | Software Development Engineer IV andy.baugh(a)webpros.com

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How should virtual users update their password?
by vwoloszczuk＠tutanota.com 13 Jan '26

13 Jan '26

Hi, I now have my email system working with virtual users, using a passwd-file for passdb. Now I am at the stage where I would like to change my password and possibly add other virtual users for my friends, who should be able to add/change their password without my involvement. I had a look at the IMAP RFCs but didn't see any sort of "change password" instruction. I also looked at the Dovecot docs but didn't see any article which covered this. What is the recommended/suggested way to do this? Is there a way to do with within the MDA/IMAP ecosystem or is it required to have an external solution e.g. entering the new password on a webpage? Thanks, Viktor Hi, I now have my email system working with virtual users, using a passwd-file for passdb. Now I am at the stage where I would like to change my password and possibly add other virtual users for my friends, who should be able to add/change their password without my involvement. I had a look at the IMAP RFCs but didn't see any sort of "change password" instruction. I also looked at the Dovecot docs but didn't see any article which covered this. What is the recommended/suggested way to do this? Is there a way to do with within the MDA/IMAP ecosystem or is it required to have an external solution e.g. entering the new password on a webpage? Thanks, Viktor

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