November 2025 - dovecot

Dovecot upgrade from 2.3.x to 2.4.x: and mailbox_alias plugin
by Gerhard Wiesinger 06 Nov '25

06 Nov '25

Hello, Regarding dovecot upgrade from 2.3.x to 2.4.x and mailbox_alias plugin: I've already converted my config and scripts but I'm still missing this config change: plugin { mailbox_alias_old = Spam mailbox_alias_new = Junk } I saw in the link https://doc.dovecot.org/2.4.0/installation/upgrade/2.3-to-2.4.html mailbox-alias plugin Depending on the use case, replacement may be the mailbox_special_use mailbox setting and/or Sieve filters. Any ideas what's the best alternative? Another question, is the following correct: mail_home = /home/vmail/%n mail_location = maildir:~/Maildir => mail_home = /home/vmail/%{user | username} mail_driver = maildir mail_path = ~/Maildir mail_inbox_path = ~/Maildir (Especially mail_inbox_path, I don't have a ".INBOX" directory currently, I guess .INBOX is now default. How to deal with this?) Thnx. Ciao, Gerhard

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Build failure due to non-constant initializers in unicode-transform.c
by adesh＠backuply.com 05 Nov '25

05 Nov '25

When building Dovecot 2.4.2 on modern compilers (GCC ≥ 5, Clang, or any C99/C11-compliant environment), the build fails in src/lib/unicode-transform.c due to the use of non-constant initializers in static const global variables. The affected lines define Hangul composition constants using other const variables instead of compile-time constants, which is not allowed in standard C99 and later. error log: unicode-transform.c:211:1: error: initializer element is not constant static const size_t uni_hangul_n_count = uni_hangul_v_count * uni_hangul_t_count; ^ unicode-transform.c:212:1: error: initializer element is not constant static const uint16_t uni_hangul_l_end = uni_hangul_l_base + uni_hangul_l_count; ^ unicode-transform.c:213:1: error: initializer element is not constant static const uint16_t uni_hangul_v_end = uni_hangul_v_base + uni_hangul_v_count; ^ unicode-transform.c:214:1: error: initializer element is not constant static const uint16_t uni_hangul_t_end = uni_hangul_t_base + uni_hangul_t_count; ^ This issue prevents building Dovecot 2.4.x on modern systems without non-standard compiler flags, breaking out-of-the-box builds on up-to-date Linux distributions.

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configuration fails at the last hurdle
by demo＠manx.net 04 Nov '25

04 Nov '25

as a newbie suddenly requiring a mail server the configuration of dovecot and postfix is proving elusive. if i get one element working another fails. i think it would help readers if i supply my status report and ask for suggestions as to how to ensure a remote client can access the mail just delivered from another remote in addition for mutt to see the mail on the sever. cat <<EOF > ~/mailserver-status.txt 📨 Mail Server Status – Ryzen2 (Ubuntu 25.10) Objective: To host email services independently, replacing Manx Telecom’s legacy offering. Rationale: Manx Telecom has been acquired by Jersey Telecom, with plans to charge £65 per annum per email address. This migration aims to preserve autonomy and reduce costs. ✅ Current Achievements - Mail Receipt Confirmed: Mail addressed to jsm(a)mckenzietrust.com (a domain owned by us) is successfully received via encrypted POP3S (port 995) using both Thunderbird and OpenSSL. - Maildir Workflow Operational: Messages arrive in Maildir/new and are moved every minute to Maildir/cur via a cron job. They are accessible locally using mutt. - SSL Layer Functional: POP3S handshake completes successfully, confirming certificate and encryption setup is sound. ⚠️ Known Issues - Remote Access Fails Silently: Thunderbird and OpenSSL clients connect but cannot retrieve messages from Maildir/cur or new. No errors are returned—access appears to die silently. - Dovecot Configuration Fragility: Any attempt to explicitly define mail_location in config files (e.g., 10-mail.conf) causes Dovecot to crash on startup. This behavior is consistent across both Ubuntu 25.04 and 25.10 builds. It is imperative not to attempt location overrides, as recovery requires reverting to a clean config state. - Post-Reboot Regression: Remote access was briefly functional but failed after a system reboot triggered by a firmware update. This suggests a state-dependent or ephemeral config success. 🧭 Configuration Notes - Dovecot and Postfix Versions: Packages from Ubuntu 25.04 were manually installed and locked to prevent auto-updates. This avoids compatibility issues with newer builds. - POP3S Listener Enabled: The following stanza is active in 10-master.conf: service pop3-login { inet_listener pop3 { port = 110 } inet_listener pop3s { port = 995 ssl = yes } } - SSL Configuration: ssl = yes ssl_server_cert_file = /etc/dovecot/private/dovecot.pem ssl_server_key_file = /etc/dovecot/private/dovecot.key These paths are valid and readable by root. 🧱 Constraints and Priorities - No Urgency: At least one month is available for debugging and refinement. - Web Server Stability Is Critical: The live web server must remain uninterrupted, as it hosts the McKenzie Trust’s public-facing structure. - Outbound Mail Deliverability: The domain currently uses DDNS. Without a PTR record, outbound mail from Ryzen2 may be rejected. A fixed IP or relay forwarding will be required. 🧩 Next Steps - Investigate mailbox visibility for remote clients—likely a permissions or UID mapping issue. - Consider enabling auth-master socket for privileged access if needed. - Explore relay options or static IP acquisition to ensure outbound mail acceptance. EOF regards jsm

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doveadm sync -1 -R only downloads Inbox but not Sent Items
by r.barclay＠habmalnefrage.de 02 Nov '25

02 Nov '25

Hi, When my free mail provider mailbox runs out of free space, I have my local Dovecot server one-way sync that free mail mailbox and then I delete the contents of the free mail mailbox. So I can archive my emails in an "offline archive". Initially, I used "doveadm backup", but later always used: doveadm -Dv sync -u offline(a)example.org -1 -f -R imapc: At large, this works. But only during the first "backup" the "Sent" folder was synced as well. Nowdays, it only downloads the Inbox, but not my Sent Items. I tried adding the "-N" parameter, but that said: "Fatal: -N parameter requires syncing with remote host" I'm on Debian 12 and Dovecot 2.3.x: 1:2.3.19.1+dfsg1-2.1+deb12u1 amd64. What could I check or try? And one more question: To better understand the debug output: What is "brain M" and "brain S"? Yours, Reg

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"Synchronization corrupted index header" with mdbox: thousands of deleted e-mails reappeared in INBOX
by Ákos Szőts 01 Nov '25

01 Nov '25

Hi everyone, Suddenly, the following messages appeared in my Dovecot error log: master: Warning: Killed with signal 15 (by pid=0 uid=0 code=kill) Error: Mailbox Trash: Synchronization corrupted index header [...]/Trash/dbox-Mails/dovecot.index: uidvalidity=0, but next_uid=73 Warning: Mailbox Trash: fscking index file [...]/Trash/dbox-Mails/dovecot.index Warning: mdbox([...]/mail/storage): rebuilding indexes: Mailbox Trash index was fsck'd Warning: mdbox([...]/mail/storage): fscking index file [...]/index/inbox/storage/dovecot.map.index Error: Mailbox INBOX: [...]/INBOX/dbox-Mails/dovecot.index reset, view is now inconsistent The first message is because I restarted the container. Since then, Thunderbird shows thousands of previously deleted e-mails again in INBOX where all my messages are marked as unread. - Do you know what can cause it and how can I avoid to happen again? - Is the used mdbox storage engine that fragile? Is the fault tolerance of other engines better? I have a backup from some days ago. Is it possible to somehow revert back to it and sync the new e-mails on top of those? Version: 2.4.2. Thank you, Ákos

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