Mailcow-dockerized: Dovecot fails to start after upgrade from state at 2019-09-25

[ProfFan]

Please try to answer all questions. If you cannot, don't just delete it. If you completely ignore or remove the whole template, your issue is either closed or ignored, too. :( This is (not only) because we are evil. Many awesome mailcow supporters don't bother to reply to an issue, when crucial information is missing. Especially when it could have been answered by using this issue template. We need as much information as possible. Please post all logs, do not copy that one line you think may be interesting. Copy the whole bunch and remove sensible information. :) Thank you!

Prior to placing the issue, please check following: (fill out each checkbox with a X once done)

• [X] I understand that not following below instructions might result in immediate closing and deletion of my issue.
• [X] I have understood that answers are voluntary and community-driven, and not commercial support.
• [X] I have verified that my issue has not been already answered in the past. I also checked previous issues.

---

Description of the bug: What kind of issue have you exactly come across?

My Dovecot stopped to respond after an upgrade of the setup today from the 2019-09-25 version (last update).

Reproduction of said bug: How exactly do you reproduce the bug?

1. I stopped all containers with docker-compose down
2. I ran the upgrade script ./update.sh and did the upgrade
3. Dovecot failed to start and SoGo shows no mailbox selected

__I have tried or I do...__ (fill out each checkbox with a X if applicable)

• [X] In case of WebUI issue, I have tried clearing the browser cache and the issue persists.
• [ ] I do run mailcow on a Synology, QNAP or any other sort of NAS.

System information

Further information (where applicable):

| Question | Answer |
| --- | --- |
| My operating system | Ubuntu 16.04.4 |
| Is Apparmor, SELinux or similar active? | Yes |
| Virtualization technlogy (KVM, VMware, Xen, etc) | KVM |
| Server/VM specifications (Memory, CPU Cores) | 2GB, 1CPU |
| Docker Version (docker version) | 19.03.5 |
| Docker-Compose Version (docker-compose version) | 1.25.1 |
| Reverse proxy (custom solution) | nginx |

Further notes:

• Output of git diff origin/master, any other changes to the code? If so, please post them.
• All third-party firewalls and custom iptables rules are unsupported. Please check the Docker docs about how to use Docker with your own ruleset. Nevertheless, iptabels output can help _us_ to help _you_: iptables -L -vn, ip6tables -L -vn, iptables -L -vn -t nat and ip6tables -L -vn -t nat

sudo iptables -L -vn
Chain INPUT (policy ACCEPT 14122 packets, 2831K bytes)
 pkts bytes target     prot opt in     out     source               destination
14122 2831K MAILCOW    all  --  *      *       0.0.0.0/0            0.0.0.0/0

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
 7492 1032K MAILCOW    all  --  *      *       0.0.0.0/0            0.0.0.0/0
 7563 1041K DOCKER-USER  all  --  *      *       0.0.0.0/0            0.0.0.0/0
 7563 1041K DOCKER-ISOLATION-STAGE-1  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
    0     0 DOCKER     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  docker0 docker0  0.0.0.0/0            0.0.0.0/0
 6188  943K ACCEPT     all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
  386 24503 DOCKER     all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0
  989 73596 ACCEPT     all  --  br-mailcow !br-mailcow  0.0.0.0/0            0.0.0.0/0
  363 23063 ACCEPT     all  --  br-mailcow br-mailcow  0.0.0.0/0            0.0.0.0/0

Chain OUTPUT (policy ACCEPT 19353 packets, 3821K bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain DOCKER (2 references)
 pkts bytes target     prot opt in     out     source               destination
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.5           tcp dpt:18080
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.5           tcp dpt:14443
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.7           tcp dpt:587
    2   120 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.7           tcp dpt:465
    2   104 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.7           tcp dpt:25
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:12345
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:4190
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.11          tcp dpt:3306
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.13          tcp dpt:8983
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:995
   19  1216 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:993
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:143
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.250         tcp dpt:110

Chain DOCKER-ISOLATION-STAGE-1 (1 references)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DOCKER-ISOLATION-STAGE-2  all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0
  989 73596 DOCKER-ISOLATION-STAGE-2  all  --  br-mailcow !br-mailcow  0.0.0.0/0            0.0.0.0/0
 7563 1041K RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0

Chain DOCKER-ISOLATION-STAGE-2 (2 references)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       all  --  *      docker0  0.0.0.0/0            0.0.0.0/0
    0     0 DROP       all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0
  989 73596 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0

Chain DOCKER-USER (1 references)
 pkts bytes target     prot opt in     out     source               destination
 7563 1041K RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0

Chain MAILCOW (2 references)
 pkts bytes target     prot opt in     out     source               destination

• Check docker exec -it $(docker ps -qf name=acme-mailcow) dig +short stackoverflow.com @172.22.1.254 (set the IP accordingly, if you changed the internal mailcow network) and docker exec -it $(docker ps -qf name=acme-mailcow) dig +short stackoverflow.com @1.1.1.1 - output? Timeout?

  • It Works

  General logs:

  • Please take a look at the official documentation.

[ProfFan]

@andryyy ls -la as per your request :)

total 140
drwxrwxr-x  7 fan  fan   4096 Jan 20 05:20 .
drwxr-xr-x 26 fan  fan   4096 Jan 20 05:49 ..
-rw-rw-r--  1 fan  fan   3223 Aug 25  2018 CODE_OF_CONDUCT.md
-rw-rw-r--  1 fan  fan    954 Aug 25  2018 CONTRIBUTING.md
drwxrwxr-x  7 fan  fan   4096 Jan 20 03:04 data
-rw-r--r--  1 root root 15819 Jan 20 04:08 docker-compose.yml
-rw-r--r--  1 root root   414 Jan 20 03:04 .editorconfig
lrwxrwxrwx  1 fan  fan     12 Aug 25  2018 .env -> mailcow.conf
-rwxr-xr-x  1 root root  8288 Jan 20 03:04 generate_config.sh
drwxrwxr-x  8 fan  fan   4096 Jan 20 05:47 .git
drwxr-xr-x  3 fan  fan   4096 Jan 29  2019 .github
-rw-r--r--  1 root root  1272 Jan 20 03:04 .gitignore
drwxrwxr-x  3 fan  fan   4096 Jan 20 03:04 helper-scripts
-rw-rw-r--  1 fan  fan  35141 Aug 25  2018 LICENSE
-rw-------  1 fan  fan   3916 Jan 20 05:20 mailcow.conf
-rw-r--r--  1 root root   662 Aug 18 02:31 README.md
-rw-rw-r--  1 fan  fan   1746 Aug 25  2018 .travis.yml
drwxr-xr-x  2 root root  4096 Jan 20 03:00 update_diffs
-rwxr-xr-x  1 root root 19393 Jan 20 02:33 update.sh

[andryyy]

Thank you. Which kernel?

[ProfFan]

@andryyy uname -r: 4.15.0-75-generic (the HWE kernel)

[andryyy]

Can you try to run down, delete all docker images and pull again?

Please also post a git diff.

Are you using overlay as storage driver?

Where did you pull that docker version from? Which repository?

[ProfFan]

I am trying that.

git diff is empty.

I am using overlay2:

Client:
 Debug Mode: false

Server:
 Containers: 1
  Running: 0
  Paused: 0
  Stopped: 1
 Images: 31
 Server Version: 19.03.5
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: b34a5c8af56e510852c35414db4c1f4fa6172339
 runc version: 3e425f80a8c931f88e6d94a8c831b9d5aa481657
 init version: fec3683
 Security Options:
  apparmor
  seccomp
   Profile: default
 Kernel Version: 4.15.0-75-generic
 Operating System: Ubuntu 16.04.6 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 1.946GiB
 Name: iZj6caj6zr3zokmd4c9y6wZ
 ID: WVVC:IHNB:WE7W:RTU7:ADY6:KFRK:SDZG:QALJ:GBOZ:DPWX:TLPQ:CGZI
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No swap limit support

Docker:

deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable

[ProfFan]

@andryyy It appears to be $(dig txt 1.4.3.spamassassin.heinlein-support.de +short | tr -d '"') returning the full DiG report instead of the +short string (1830).

Log:

dovecot-mailcow_1    | curl: (6) Could not resolve host: ;
dovecot-mailcow_1    | curl: (6) Could not resolve host: <<>>
dovecot-mailcow_1    | curl: (6) Could not resolve host: DiG
dovecot-mailcow_1    | curl: (6) Could not resolve host: 9.11.5-P4-5.1-Debian
dovecot-mailcow_1    | curl: (6) Could not resolve host: <<>>
dovecot-mailcow_1    | curl: (6) Could not resolve host: txt
dovecot-mailcow_1    | curl: (6) Could not resolve host: 1.4.3.spamassassin.heinlein-support.de
dovecot-mailcow_1    | curl: (6) Could not resolve host: +short
dovecot-mailcow_1    | curl: (6) Could not resolve host: ;;
dovecot-mailcow_1    | curl: (6) Could not resolve host: global
dovecot-mailcow_1    | curl: (6) Could not resolve host: options
dovecot-mailcow_1    | curl: (6) Could not resolve host: +cmd
dovecot-mailcow_1    | curl: (6) Could not resolve host: ;;
dovecot-mailcow_1    | curl: (6) Could not resolve host: connection

[ProfFan]

@andryyy I have fixed the issue by terminating the curl process 🤣

sudo docker exec -it $(sudo docker ps -qf name=dovecot-mailcow) killall curl

[andryyy]

Please use the original images as provided for download. It kind of sounds like the images were built with broken scripts (line endings?).

If you build them, make sure the format is unchanged. :)

This should not be considered a workaround. The default images work fine. :)

Edit: This is just what I assume might be the error here. I booted an Ubuntu 16.04 with that kernel and it worked fine.

[ProfFan]

@andryyy actually the images are pulled right from the docker hub (I deleted all images and repulled), same error.

[andryyy]

Sorry, don't don't why this would happen then. I cannot replicate that issue locally. Would need to see it on the server and do some tests.

[ProfFan]

It is indeed very strange...

BTW, my kernel:

Linux iZj6caj6zr3zokmd4c9y6wZ 4.15.0-75-generic #85~16.04.1-Ubuntu SMP Wed Jan 15 12:30:12 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ sudo apt show docker-ce
Package: docker-ce
Version: 5:19.03.5~3-0~ubuntu-xenial
Priority: optional
Section: admin
Maintainer: Docker <[email protected]>
Installed-Size: 109 MB
Depends: docker-ce-cli, containerd.io (>= 1.2.2-3), iptables, libseccomp2 (>= 2.3.0), libc6 (>= 2.8), libdevmapper1.02.1 (>= 2:1.02.97), libsystemd0
Recommends: aufs-tools, ca-certificates, cgroupfs-mount | cgroup-lite, git, pigz, xz-utils, libltdl7, apparmor
Conflicts: docker (<< 1.5~), docker-engine, docker-engine-cs, docker.io, lxc-docker, lxc-docker-virtual-package
Replaces: docker-engine
Homepage: https://www.docker.com
Download-Size: 22.8 MB
APT-Manual-Installed: yes
APT-Sources: https://download.docker.com/linux/ubuntu xenial/stable amd64 Packages

[ProfFan]

@andryyy It's fine :) I will investigate further tomorrow to see what the problem actually is.

Plus: it is actually a big plus if you can turn on bash tracing (set -x) in the bash scripts that downloads the spam list in dovecot image :)

[andryyy]

Where is your VM hosted? Which filesystem? I can try to replicate it there.

[ProfFan]

It is hosted on Aliyun (Alibaba Cloud), filesystem is ext4.

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.6 LTS
Release:    16.04
Codename:   xenial

Last update at:

commit c97dd9b30e310abb2e0b69f2efab6c0e996e241c
Merge: 18ebd53 8b453ab
Author: moo <[email protected]>
Date:   Wed Sep 25 07:09:51 2019 +0800

    After update on 2019-09-25_07_04_17

commit 18ebd532050d003e025d87055c48132d8f737242
Author: moo <[email protected]>
Date:   Wed Sep 25 07:09:48 2019 +0800

    Before update on 2019-09-25_07_04_17

commit 8b453ab803a2f9917e8a5e9d77ed585a9e39d60a
Author: andryyy <[email protected]>
Date:   Tue Sep 24 19:12:20 2019 +0200

    [Web] Allow to set sogo_visible when adding an alias, fixes #2975

commit 14a2a266a1388b195c7cdf419f6ec65c046069a6
Author: andryyy <[email protected]>
Date:   Tue Sep 24 18:34:08 2019 +0200

    [Web] Improve U2F process and fix Win 1903 hassle

[Tominator89]

try run "docker-compose logs --tail=100 dovecot-mailcow"

my dovecot can not find the config file, which is not in the right place /var/run/dovecot/dovecot.conf

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[ProfFan]

After half a year I was struck with this again. But this time, I am pretty sure that this is an issue with mailcow itself. Here are my observations and solution:

1. This happens each time I try to update mailcow-dockerized
2. This:

sudo docker exec -it $(sudo docker ps -qf name=dovecot-mailcow) dig txt 1.4.3.spamassassin.heinlein-support.de +short @172.22.1.254

returns

; <<>> DiG 9.11.5-P4-5.1-Debian <<>> txt 1.4.3.spamassassin.heinlein-support.de +short @172.22.1.254
;; global options: +cmd
;; connection timed out; no servers could be reached

1. but if I run this for more than one time, sometimes this works, returning "1883"
2. Thus I think this error is caused by the spam list download script not having a sane retry logic, so dovecot is blocked by the download
3. The problem is solved by restarting dovecot: sudo docker restart mailcowdockerized_dovecot-mailcow_1

However, it would be really nice if this can be fixed by the upstream. CC @andryyy

[ProfFan]

Attaching the logs to help reproduce what is happening:

dovecot-mailcow_1    | Uptime: 4  Threads: 8  Questions: 25  Slow queries: 0  Opens: 26  Flush tables: 1  Open tables: 18  Queries per second avg: 6.250
dovecot-mailcow_1    | Adding user `vmail' to group `tty' ...
dovecot-mailcow_1    | Adding user vmail to group tty
dovecot-mailcow_1    | Done.
dovecot-mailcow_1    |   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
dovecot-mailcow_1    |                                  Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0Warning: Transient problem: timeout Will retry in 1 seconds. 10 retries left.
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0Warning: Transient problem: timeout Will retry in 2 seconds. 9 retries left.
100    43  100    43    0     0     47      0 --:--:-- --:--:-- --:--:--    47
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 1 seconds. 10 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 2 seconds. 9 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 4 seconds. 8 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 8 seconds. 7 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 16 seconds. 6 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 32 seconds. 5 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 64 seconds. 4 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 128 seconds. 3 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 256 seconds. 2 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 512 seconds. 1 retries left.
dovecot-mailcow_1    | curl: (6) Could not resolve host: ;
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 1 seconds. 10 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 2 seconds. 9 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 4 seconds. 8 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 8 seconds. 7 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 16 seconds. 6 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 32 seconds. 5 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 64 seconds. 4 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 128 seconds. 3 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 256 seconds. 2 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 512 seconds. 1 retries left.
dovecot-mailcow_1    | curl: (6) Could not resolve host: <<>>
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 1 seconds. 10 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 2 seconds. 9 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 4 seconds. 8 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 8 seconds. 7 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 16 seconds. 6 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 32 seconds. 5 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 64 seconds. 4 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 128 seconds. 3 retries left.
dovecot-mailcow_1    | Warning: Transient problem: timeout Will retry in 256 seconds. 2 retries left.

After restart:

dovecot-mailcow_1    | Uptime: 2531  Threads: 16  Questions: 7343  Slow queries: 0  Opens: 92  Flush tables: 3  Open tables: 31  Queries per second avg: 2.901
dovecot-mailcow_1    | The user `vmail' is already a member of `tty'.
dovecot-mailcow_1    |   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
dovecot-mailcow_1    |                                  Dload  Upload   Total   Spent    Left  Speed
100   98k  100   98k    0     0  32190      0  0:00:03  0:00:03 --:--:-- 32200
dovecot-mailcow_1    | 20_blatspammer.cf
dovecot-mailcow_1    | 70_HS_body.cf
dovecot-mailcow_1    | 70_HS_header.cf
dovecot-mailcow_1    | {"msg":"command completed successfully","type":"success"}
dovecot-mailcow_1    | 2020-06-05 05:02:55,277 INFO Set uid to user 0 succeeded
dovecot-mailcow_1    | 2020-06-05 05:02:55,287 INFO supervisord started with pid 1
dovecot-mailcow_1    | 2020-06-05 05:02:56,294 INFO spawned: 'processes' with pid 123
dovecot-mailcow_1    | 2020-06-05 05:02:56,296 INFO spawned: 'cron' with pid 124
dovecot-mailcow_1    | 2020-06-05 05:02:56,320 INFO spawned: 'dovecot' with pid 125
dovecot-mailcow_1    | 2020-06-05 05:02:56,322 INFO spawned: 'syslog-ng' with pid 126
dovecot-mailcow_1    | [2020-06-05T05:02:56.965269] WARNING: With use-dns(no), dns-cache() will be forced to 'no' too!;
dovecot-mailcow_1    | Jun  5 05:02:56 mail syslog-ng[126]: syslog-ng starting up; version='3.19.1'
dovecot-mailcow_1    | 2020-06-05 05:02:57,996 INFO success: processes entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
dovecot-mailcow_1    | 2020-06-05 05:02:57,997 INFO success: cron entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
dovecot-mailcow_1    | 2020-06-05 05:02:57,997 INFO success: dovecot entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
dovecot-mailcow_1    | 2020-06-05 05:02:57,997 INFO success: syslog-ng entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)

Please note here:

dovecot-mailcow_1    | curl: (6) Could not resolve host: ;

These are probably caused by the script not checking for wget returning an error and blindly using the data in subsequent calls.

[andryyy]

Not related to an update at all.
DNS inside the container seems broken.

Again: not related to an update.

[andryyy]

Please check your setup. There are so many possible misconfigurations leading to a failing DNS. All are related to your network and I am not willing to give out free hands-on anymore.

I can assure you it is not a problem _we_ need to fix. But I'm also not able to provide free hands-on support to everyone anymore. I did this too often. :(
The reason you encountered this error _again_ sounds like you never really fixed your system.

Check why resolving fails. The only change in the image was a line in a Python script. ;) I doubt that broke DNS resolving.

There are support packages for exactly these problems. I _will_ find the problem, when getting my hands on it. And it will definitely be a network problem. :)

[nightah]

I experienced the same symptoms described here and it was because I still had IPv6 enabled in mailcow (the default) but didn’t have it enabled on the host.

We tried looking at fallback options for Unbound but I don’t believe there’s anything that can prevent the issue. So we ended up documenting a fix here.

If you have the ability to support IPv6 turn it on. If not, you should disable it in mailcow.

[Adorfer]

If you have the ability to support IPv6 turn it on. If not, you should disable it in mailcow.

seconded, since "delivery via IPv6" is less likely to be flagged false positivly as SPAM. there seems to be a "ipv6 bonus".

But to the topic: I would suggest to have more sanity checks in mailcow (each with manual override)
eg.

• testing unbound (ipv4, ipv6)
• testing forward/ptr-dns hosthname for local IPv4 and v6
• testing of architecture of the docker-bridge (to prevent becoming a spam relay)
• warning for low RAM (in conflict with config settings eg. FTS and threadvalues)

[andryyy]

@nightah was it fixed for you with do-ipv6: no?

[nightah]

@nightah was it fixed for you with do-ipv6: no?

That’s right @andryyy.

I’m not sure if you remember but one of the other symptoms was that often the first PTR lookup for a set of addresses would often take 6-9 seconds, which would also result in additional rspamd headers for not being able to resolve the reverse address in time.

You can disable ipv6 entirely or just change the Unbound setting per your post.