Da die Frage immer wieder aufkommt und es schwierig ist ein für den Mailserverbetrieb geeignetes ASN zu finden, kann ich heute ruhigen Gewissens Lennarts ETH-Services empfehlen.

Lennart ist selber in der mailcow Community aktiv und kennt die Kniffe zum Betrieb eines Mailservers.

Für einen reibungslosen Betrieb einer mailcow empfehle ich den VPS Gianfar.

Es ist eine aufrichtige, nicht bezahlte und gut gemeinte Empfehlung.

Zusammen mit unserem mailcow Support steht dem Betrieb nichts mehr im Weg. 😉

Hello mailcow folks 🐄,

"After update is before update", so always update your cows please, no matter if there is a summary on mailcow.email. 🙂

Before we start I want to remind you of an important change that’s about to happen tomorrow:

mailcow, including me, will be part of "The Infrastructure Company GmbH". No, mailcow will not be discontinued. No, I will not stop to work on mailcow.
You will probably not notice the change at all. Hopefully we will be able to finally implement more features soon as there will be more time to work on mailcow.

We still rely heavily on your support (support contacts, SAL etc.) to continue mailcow as it is. As long as we don’t have a commercial plan or "paid version" of mailcow, that’s the only way for us to finance the work on mailcow.

What’s new?

Many bugs were fixed and existing features were cleaned up.

What’s next?

Disclaimers/signatures with variables to use in a pre-defined template per domain and mailbox. 🙂


Thank you guys for your amazing support and contributions! Especially language updates/fixes and additions are very welcome!

[ACME] Skip inactive domains
[API docs] Add sogo_visible property to alias endpoints (#3956)
[Alpine] Update Alpine base images to v3.13
[Api docs] Added day ratelimit option to /add/domain endpoint
[Backup Helper] Possible workaround for #3913
[ClamAV] Update to 0.103.1
[Compose] Update ClamAV image
[Config] Add ADDITIONAL_SERVER_NAMES as optional config to define additional server_name parameters for mailcow UI
[Config] Add Wikipedia link for TZ values (#3891)
[Config] Fix binding problems with IPv6 in newer Docker versions
[Config] Remove example
[Docker 20.10 Fix] Fix for moby/moby#39837, fixes #3893
[Dovecot] Add Russian and Ukrainian folders (#3967)
[Dovecot] Add sieve rule to move DeltaChat (https://delta.chat) messages to folder DeltaChat
[Dovecot] Check if quarantine_notify.py holds a lock
[Dovecot] Remove Schaal, remove non-numeric TXT output from dig request
[Dovecot] Replace hostname for quarantine notifications with mailcow hostname (broke after Docker 20.10 fix)
[Dovecot] Set –addheader by default, fixes #4025
[Git] Ignore SSL examples
[Git] Ignore custom SOGo logo
[Git] Ignore custom-themes.js in SOGo
[Git] Sort gitignore
[Helper] Use NC 20
[MariaDB] Update to 10.5
[Netfilter] Further improvements to catch invalid input
[Netfilter] Restart on invalid data via pubsub
[Nginx] Be more explicit with server names
[Olefy] Update container to alpine 3:13 to fix build (#3988)
[PHP-FPM] Add sleep to loop
[PHP-FPM] Fix fastcgi timeouts
[PHP-FPM] Increase PHP memory limit for "cli" to 512M (#4010)
[PHP-FPM] Update image
[Postfix] Add parent_domain_matches_subdomains
[Postfix] Add postscreen whitelist syntax and examples (#3931)
[Postfix] Do not create a TLS SNI map when SKIP_LETS_ENCRYPT=y
[Postfix] Fix HELO name
[Postfix] Unset Postfix smtpd_tls_session_cache_database, reduce disk writes (#3981)
[Postfix] Use tmpfs for watchdog’s /tmp, reduce disk writes (#3923)
[Rspamd] Add FUZZY_SPAM_MISMATCH (#3958)
[Rspamd] Add bulk header
[Rspamd] Block spoofing for free mail domains (#3907)
[Rspamd] Edit RBL
[Rspamd] Fix vanished Rspamd history after restart
[Rspamd] Increase spam symbol weight
[Rspamd] Not trigger FREEMAIL_POLICY for mailig lists (#3918)
[Rspamd] Remove ham symbols if a fuzzy denied hash matched
[Rspamd] Score for freemail from to undisclosed recipients
[Rspamd] Set bounce_to ratelimit to 7 / 1m to hopefully reduce backscatter spam
[Rspamd] Sort & add infos for bad ASN map (#3934)
[SOGo] Add custom favicon (#3957)
[SOGo] Fix comments in custom theme
[SOGo] Remove custom theme, disable debug mode, keep example custom-themes
[Update, Config] Add subject for watchdog emails (#4027)
[Update] Better GLIBC check
[Update] Try to determine GLIBC version
[Watchdog] Longer sleep for open relay check
[Watchdog] Return score with Rspamd check
[Watchdog] Revert to Alpine 3.11, needs fixes
[Watchdog] Temp. disable query check
[Web] Changed type of items parameter to list
[Web] Accept prehashes password on both edit and add mailbox
[Web] Accept raw SSHA hashes as passwords
[Web] Add SSHA
[Web] Add Trustkey CA for WebAuthn
[Web] Add information about extended DNS config
[Web] Add nevondo.com ip check source, thank you!
[Web] Added missing french parts, based on the english file
[Web] Allow to specify transport test rcpt
[Web] Danish lang. 🇩🇰 (#3971)
[Web] Do not cache content of Rspamd global filter maps
[Web] Do not create 2M session file when saving large Rspamd global filter maps (thanks @Drago)
[Web] Do not print invalid date
[Web] Feature: Expand alias over alias domains
[Web] Feature: Expand alias over alias domains
[Web] Fix SSO for SOGo when authen with FIDO2, thanks to Drago!
[Web] Fix U2F file
[Web] Fix attachment download, thanks to Drago
[Web] Fix duplicate file extension on shortened filenames
[Web] Fix for listing mailboxes and aliases from multiple domains (#3996)
[Web] Fix more ACL-disabled buttons
[Web] Fix quota-left calculations when editing a mailbox (respect max domain quota)
[Web] Fix textarea number width > 999
[Web] Implement all supported dovecot password schemas (#3974)
[Web] Keep state of quarantine table in session
[Web] Missing capital letters on some buttons (#4000)
[Web] Move white/blacklist form above the table (#3975)
[Web] Remove 36f296d9d63112db4218cef39f1eebc8a61c785d, fixes #3926
[Web] Remove breakpoints for small screens for "Recipient" and "Action" columns (#3938)
[Web] Show JID example when editing a domain
[Web] Show quarantine settings in /quarantine
[Web] Temp remove ip6.korves.net
[Web] Update libs
[Web] Update russian translation (lang.ru.json)
[Web] Uppercase "rename" in en and de
[Web] Use api/v1/get/mailbox/reduced for faster loading of mailbox table
[Web] Various small fixes and enhancements
[mailcow] Fix C22 -> C2S

Thanks to Andreas we recently discovered something great…


…and its name is Delta Chat!

Before you move away: No, it is not yet another messenger. Or is it?

It is something in between. Delta Chat uses email to transport its messages. Your email server.

  • Delta Chat does work with "autoconfig". Enter your mailcow email address and password and your are ready!
  • Delta Chat automatically encrypts messages using Autocrypt – no setup needed!
  • mailcow comes with a sieve prefilter to move all chats to the preconfigured DeltaChat folder (since commit 3dece1)
  • Communicate with any email recipient, every client uses their own email server.

So what do I need?

  • The app, get it here
  • A mailcow or basically any other email account

…and 2021 is just around the corner! 🎆

It’s an understatement to say that 2020 was a strange year and, for sure, challenging for many of us in so many different aspects. I hope you’re fine and enjoyed your recent days with your loved ones.

If you don’t want to read further:
We wish you a very happy New Year! 🎉

😻 To focus on the positive things from a mailcow point-of-view, there were indeed quite some highlights in 2020:

  • Early this year external open relay checks were implemented for SAL users (supporting the development) was introduced. (see news)
  • In February 2020 our own fuzzy storage was launched, improving spam detection for all mailcow users and allowing to contribute spam emails. (see news)
  • In March 2020 we’ve started a official community forum with great success.
  • In July 2020 our sponsored improvements for the new identity management to SOGo made it into the public release: check it out!
  • Access to IMAP, POP3 and SMTP can now be controlled on a per-user level, also last logins for each service can be seen in the webinterface. (see news)
  • FIDO2/WebAuthn support was added to mailcow in November 2020. (see news)
  • You can easily integrate your mailpiler instance – open-source-based email archiving solution – with mailcow: see docs.
  • Also good to know: Deprecated TLS versions TLSv1.0 and TLSv1.1 were disabled, mailcow can now speak Romanian and Chinese.

📝 Two more things I want to note…

✍️ First… Telegram.
In July 2019 we’ve started with a Telegram group for mailcow, where – to date – joined over 920 individual, awesome people! The positive feedback, how people help each other and the new friendships found this way… It’s unbelievable!

Thanks for being part of this community. This is what makes our community that great: It’s made up by awesome people – like YOU.

❤️ Second… Contributors.
THANKS for every contribution – and it doesn’t matter if it’s helping other people, sharing the mooo, contributing code or simply silently using mailcow somewhere.

Also there’s something what we might often take for granted: mailcow consists out of so many different components, where people invest their valuable time in and provide it for free to everyone.

Thanks for all the good work from people behind Postfix, Dovecot, rspamd, Docker, SOGo, unbound, clamav, LetsEncrypt and so many more. Mailcow wouldn’t exist without you.

That being said…
Thanks for all, stay healthy and Happy New Year. 😘

Patrik and Andre

Welcome FIDO2 to mailcow!

We recently pushed a change to integrate FIDO2/WebAuthn support for administrators and domain administrators to mailcow.

mailcow FIDO2

Please see our docs for further information.

We are working to be listed on Works with Yubi in the near feature.

Quick note: A single SMTP recipient "postmaster@…" is now whitelisted by default.

Previously we included a settings map template to manually enable this behavior. This template is now dropped. It does not hurt to keep the old settings map, it will just never be applied.

Same for outbound: No matter the authentication, a SMTP FROM postmaster@… will be score -2500.00. No prefilter is applied to keep signatures.

-2500.0 will also skip ClamAV-positives, please keep that in mind, do not forward viruses.


It’s been a long time since I wrote other posts than updates.

My daughter was born almost a year ago. My life changed quite a lot, I still don’t feel like I reached my goals and that there is going to be more fantastic changes to come. Thank you guys for contributing to mailcow and enlighten my day – every day.

InterServer started contributing fuzzy hashes to mailcow. If you have a spam trap by hand and feel like sharing, please contact me. Thank you, InterServer; thank you, John.

What could be next?

  • I will try to add hooks to mailcow UI. I want to implement individual hooks that can run after adding a domain, mailbox or other elements. The "push" hook like we already have with Pushover will be moved to that logic. Users will be able to control push hooks, domain admins as well as admins will be able to add hooks to other logics like adding a mailbox, domain or alias etc.

  • I will add a HTTP map to resolve aliases to their final recipients. This way we can finally fix the tag handling for alias recipients and make black/whitelistings more granular.

Please join us on Telegram, if you have ideas to share or just want to hang out. 🙂