Update from nginx to version 3.18 results in nginx not starting

[BigPig22]

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Description

I updated my system and nginx wont start anymore.
After some searching I found that the nginx container has received an update yesterday to version 3.18.

Switching back to version 3.17 fixes the issue.

Logs:

sudo docker compose logs --tail=200 nginx-mailcow
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error
nginx-mailcow-1  | exec /docker-entrypoint.sh: exec format error

Steps to reproduce:

1. Do a docker compose up -d to update to the latest nginx container
2. Nginx wont start
3. Revert to nginx:mainline-alpine3.17 and everything is working

Which branch are you using?

master

Which architecture are you using?

x86

Operating System:

Ubuntu 22.04 LTS

Server/VM specifications:

8GB, 2 Cores

Is Apparmor, SELinux or similar active?

no

Virtualization technology:

KVM

Docker version:

25.0.3

docker-compose version or docker compose version:

v2.24.5

mailcow version:

2024-02

Reverse proxy:

Caddy

Logs of git diff:

diff --git a/data/assets/ssl-example/cert.pem b/data/assets/ssl-example/cert.pem
index 96d16bec..ec988261 100644
--- a/data/assets/ssl-example/cert.pem
+++ b/data/assets/ssl-example/cert.pem
@@ -1,19 +1,33 @@
 -----BEGIN CERTIFICATE-----
-
 -----END CERTIFICATE-----
diff --git a/data/assets/ssl-example/key.pem b/data/assets/ssl-example/key.pem
index cedf35a0..481fca94 100644
--- a/data/assets/ssl-example/key.pem
+++ b/data/assets/ssl-example/key.pem
@@ -1,27 +1,52 @@
------BEGIN RSA PRIVATE KEY-----
-
------END RSA PRIVATE KEY-----
+-----BEGIN PRIVATE KEY-----
+
+-----END PRIVATE KEY-----
diff --git a/data/conf/postfix/main.cf b/data/conf/postfix/main.cf
index 572300db..1026acd8 100644
--- a/data/conf/postfix/main.cf
+++ b/data/conf/postfix/main.cf
@@ -173,3 +173,36 @@ parent_domain_matches_subdomains = debug_peer_list,fast_flush_domains,mynetworks

 # DO NOT EDIT ANYTHING BELOW #
 # Overrides #
+
+postscreen_dnsbl_sites = wl.mailspike.net=127.0.0.[18;19;20]*-2
+  hostkarma.junkemailfilter.com=127.0.0.1*-2
+  list.dnswl.org=127.0.[0..255].0*-2
+  list.dnswl.org=127.0.[0..255].1*-4
+  list.dnswl.org=127.0.[0..255].2*-6
+  list.dnswl.org=127.0.[0..255].3*-8
+  ix.dnsbl.manitu.net*2
+  bl.spamcop.net*2
+  bl.suomispam.net*2
+  hostkarma.junkemailfilter.com=127.0.0.2*3
+  hostkarma.junkemailfilter.com=127.0.0.4*2
+  hostkarma.junkemailfilter.com=127.0.1.2*1
+  backscatter.spameatingmonkey.net*2
+  bl.ipv6.spameatingmonkey.net*2
+  bl.spameatingmonkey.net*2
+  b.barracudacentral.org=127.0.0.2*7
+  bl.mailspike.net=127.0.0.2*5
+  bl.mailspike.net=127.0.0.[10;11;12]*4
+  dnsbl.sorbs.net=127.0.0.10*8
+  dnsbl.sorbs.net=127.0.0.5*6
+  dnsbl.sorbs.net=127.0.0.7*3
+  dnsbl.sorbs.net=127.0.0.8*2
+  dnsbl.sorbs.net=127.0.0.6*2
+  dnsbl.sorbs.net=127.0.0.9*2
+  zen.spamhaus.org=127.0.0.[10;11]*8
+  zen.spamhaus.org=127.0.0.[4..7]*6
+  zen.spamhaus.org=127.0.0.3*4
+  zen.spamhaus.org=127.0.0.2*3
+
+# User Overrides
+myhostname = mail01.fragel.network
+
diff --git a/data/conf/sogo/sogo.conf b/data/conf/sogo/sogo.conf
index 8d4dd93d..ea4701fb 100644
--- a/data/conf/sogo/sogo.conf
+++ b/data/conf/sogo/sogo.conf
@@ -5,7 +5,7 @@
         PrivateDAndTViewer
     );

-    WOWorkersCount = "20";
+    WOWorkersCount = "40";
     SOGoACLsSendEMailNotifications = YES;
     SOGoAppointmentSendEMailNotifications = YES;
     SOGoDraftsFolderName = "Drafts";
diff --git a/docker-compose.yml b/docker-compose.yml
index ea56b429..0ff8446a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -359,7 +359,7 @@ services:
         - sogo-mailcow
         - php-fpm-mailcow
         - redis-mailcow
-      image: nginx:mainline-alpine
+      image: nginx:mainline-alpine3.17
       dns:
         - ${IPV4_NETWORK:-172.22.1}.254
       command: /bin/sh -c "envsubst < /etc/nginx/conf.d/templates/listen_plain.template > /etc/nginx/conf.d/listen_plain.active &&
@@ -609,36 +609,6 @@ services:
           aliases:
             - ofelia

-    ipv6nat-mailcow:
-      depends_on:
-        - unbound-mailcow
-        - mysql-mailcow
-        - redis-mailcow
-        - clamd-mailcow
-        - rspamd-mailcow
-        - php-fpm-mailcow
-        - sogo-mailcow
-        - dovecot-mailcow
-        - postfix-mailcow
-        - memcached-mailcow
-        - nginx-mailcow
-        - acme-mailcow
-        - netfilter-mailcow
-        - watchdog-mailcow
-        - dockerapi-mailcow
-        - solr-mailcow
-      environment:
-        - TZ=${TZ}
-      image: robbertkl/ipv6nat
-      security_opt:
-        - label=disable
-      restart: always
-      privileged: true
-      network_mode: "host"
-      volumes:
-        - /var/run/docker.sock:/var/run/docker.sock:ro
-        - /lib/modules:/lib/modules:ro
-
 networks:
   mailcow-network:
     driver: bridge

Logs of iptables -L -vn:

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
40554   22M DOCKER-USER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
40554   22M DOCKER-ISOLATION-STAGE-1  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
32645   17M ACCEPT     all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
 2216  143K DOCKER     all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0           
 4979 4006K ACCEPT     all  --  br-mailcow !br-mailcow  0.0.0.0/0            0.0.0.0/0           
 2169  140K ACCEPT     all  --  br-mailcow br-mailcow  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           
  369  144K ACCEPT     all  --  *      br-749f493bd56e  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
   39  2496 DOCKER     all  --  *      br-749f493bd56e  0.0.0.0/0            0.0.0.0/0           
  321  900K ACCEPT     all  --  br-749f493bd56e !br-749f493bd56e  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  br-749f493bd56e br-749f493bd56e  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  *      br-fa651271febc  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
    0     0 DOCKER     all  --  *      br-fa651271febc  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  br-fa651271febc !br-fa651271febc  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  br-fa651271febc br-fa651271febc  0.0.0.0/0            0.0.0.0/0           

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain DOCKER (4 references)
 pkts bytes target     prot opt in     out     source               destination         
   39  2496 ACCEPT     tcp  --  !br-749f493bd56e br-749f493bd56e  0.0.0.0/0            172.18.0.2           tcp dpt:8080
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.5           tcp dpt:8983
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.249         tcp dpt:6379
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.6           tcp dpt:3306
    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            172.22.1.250         tcp dpt:995
    2   100 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
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.253         tcp dpt:587
    0     0 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.253         tcp dpt:465
    2   120 ACCEPT     tcp  --  !br-mailcow br-mailcow  0.0.0.0/0            172.22.1.253         tcp dpt:25

Chain DOCKER-ISOLATION-STAGE-1 (1 references)
 pkts bytes target     prot opt in     out     source               destination         
 4979 4006K DOCKER-ISOLATION-STAGE-2  all  --  br-mailcow !br-mailcow  0.0.0.0/0            0.0.0.0/0           
    0     0 DOCKER-ISOLATION-STAGE-2  all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0           
  321  900K DOCKER-ISOLATION-STAGE-2  all  --  br-749f493bd56e !br-749f493bd56e  0.0.0.0/0            0.0.0.0/0           
    0     0 DOCKER-ISOLATION-STAGE-2  all  --  br-fa651271febc !br-fa651271febc  0.0.0.0/0            0.0.0.0/0           
45698   24M RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain DOCKER-ISOLATION-STAGE-2 (4 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DROP       all  --  *      br-mailcow  0.0.0.0/0            0.0.0.0/0           
    0     0 DROP       all  --  *      docker0  0.0.0.0/0            0.0.0.0/0           
    0     0 DROP       all  --  *      br-749f493bd56e  0.0.0.0/0            0.0.0.0/0           
    0     0 DROP       all  --  *      br-fa651271febc  0.0.0.0/0            0.0.0.0/0           
 6293 5292K 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         
45698   24M RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0

Logs of ip6tables -L -vn:

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
10546   12M DOCKER-USER  all      *      *       ::/0                 ::/0                
10546   12M DOCKER-ISOLATION-STAGE-1  all      *      *       ::/0                 ::/0                
 4735   11M ACCEPT     all      *      br-mailcow  ::/0                 ::/0                 ctstate RELATED,ESTABLISHED
 4709  339K DOCKER     all      *      br-mailcow  ::/0                 ::/0                
 1102  104K ACCEPT     all      br-mailcow !br-mailcow  ::/0                 ::/0                
 4709  339K ACCEPT     all      br-mailcow br-mailcow  ::/0                 ::/0                
    0     0 ACCEPT     all      *      docker0  ::/0                 ::/0                 ctstate RELATED,ESTABLISHED
    0     0 DOCKER     all      *      docker0  ::/0                 ::/0                
    0     0 ACCEPT     all      docker0 !docker0  ::/0                 ::/0                
    0     0 ACCEPT     all      docker0 docker0  ::/0                 ::/0                

Chain OUTPUT (policy ACCEPT 0 packets, 0 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                 fd4d:6169:6c63:6f77::b  tcp dpt:4190
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::b  tcp dpt:995
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::b  tcp dpt:993
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::b  tcp dpt:143
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::b  tcp dpt:110
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::f  tcp dpt:587
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::f  tcp dpt:465
    0     0 ACCEPT     tcp      !br-mailcow br-mailcow  ::/0                 fd4d:6169:6c63:6f77::f  tcp dpt:25

Chain DOCKER-ISOLATION-STAGE-1 (1 references)
 pkts bytes target     prot opt in     out     source               destination         
 1102  104K DOCKER-ISOLATION-STAGE-2  all      br-mailcow !br-mailcow  ::/0                 ::/0                
    0     0 DOCKER-ISOLATION-STAGE-2  all      docker0 !docker0  ::/0                 ::/0                
    0     0 DOCKER-ISOLATION-STAGE-2  all      br-749f493bd56e !br-749f493bd56e  ::/0                 ::/0                
    0     0 DOCKER-ISOLATION-STAGE-2  all      br-fa651271febc !br-fa651271febc  ::/0                 ::/0                
14625   13M RETURN     all      *      *       ::/0                 ::/0                

Chain DOCKER-ISOLATION-STAGE-2 (4 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DROP       all      *      br-mailcow  ::/0                 ::/0                
    0     0 DROP       all      *      docker0  ::/0                 ::/0                
    0     0 DROP       all      *      br-749f493bd56e  ::/0                 ::/0                
    0     0 DROP       all      *      br-fa651271febc  ::/0                 ::/0                
 1500  141K RETURN     all      *      *       ::/0                 ::/0                

Chain DOCKER-USER (1 references)
 pkts bytes target     prot opt in     out     source               destination         
14625   13M RETURN     all      *      *       ::/0                 ::/0

Logs of iptables -L -vn -t nat:

Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
  169 16685 DOCKER     all  --  *      *       0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type LOCAL

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DOCKER     all  --  *      *       0.0.0.0/0           !127.0.0.0/8          ADDRTYPE match dst-type LOCAL

Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
 2527  190K MASQUERADE  all  --  *      !br-mailcow  172.22.1.0/24        0.0.0.0/0           
    0     0 MASQUERADE  all  --  *      !docker0  172.17.0.0/16        0.0.0.0/0           
    0     0 MASQUERADE  all  --  *      !br-749f493bd56e  172.18.0.0/16        0.0.0.0/0           
    0     0 MASQUERADE  all  --  *      !br-fa651271febc  172.19.0.0/16        0.0.0.0/0           
    0     0 MASQUERADE  tcp  --  *      *       172.18.0.2           172.18.0.2           tcp dpt:8080
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.5           172.22.1.5           tcp dpt:8983
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.249         172.22.1.249         tcp dpt:6379
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.6           172.22.1.6           tcp dpt:3306
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:12345
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:4190
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:995
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:993
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:143
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.250         172.22.1.250         tcp dpt:110
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.253         172.22.1.253         tcp dpt:587
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.253         172.22.1.253         tcp dpt:465
    0     0 MASQUERADE  tcp  --  *      *       172.22.1.253         172.22.1.253         tcp dpt:25

Chain DOCKER (2 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 RETURN     all  --  br-mailcow *       0.0.0.0/0            0.0.0.0/0           
    0     0 RETURN     all  --  docker0 *       0.0.0.0/0            0.0.0.0/0           
    0     0 RETURN     all  --  br-749f493bd56e *       0.0.0.0/0            0.0.0.0/0           
    0     0 RETURN     all  --  br-fa651271febc *       0.0.0.0/0            0.0.0.0/0           
   39  2496 DNAT       tcp  --  !br-749f493bd56e *       0.0.0.0/0            0.0.0.0/0            tcp dpt:8089 to:172.18.0.2:8080
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            127.0.0.1            tcp dpt:18983 to:172.22.1.5:8983
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            127.0.0.1            tcp dpt:7654 to:172.22.1.249:6379
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            127.0.0.1            tcp dpt:13306 to:172.22.1.6:3306
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            127.0.0.1            tcp dpt:19991 to:172.22.1.250:12345
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:4190 to:172.22.1.250:4190
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:995 to:172.22.1.250:995
    2   100 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:993 to:172.22.1.250:993
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:143 to:172.22.1.250:143
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:110 to:172.22.1.250:110
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:587 to:172.22.1.253:587
    0     0 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:465 to:172.22.1.253:465
    2   120 DNAT       tcp  --  !br-mailcow *       0.0.0.0/0            0.0.0.0/0            tcp dpt:25 to:172.22.1.253:25

Logs of ip6tables -L -vn -t nat:

Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DOCKER     all      *      *       ::/0                 ::/0                 ADDRTYPE match dst-type LOCAL

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DOCKER     all      *      *       ::/0                !::1                  ADDRTYPE match dst-type LOCAL

Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
 1080  102K MASQUERADE  all      *      !br-mailcow  fd4d:6169:6c63:6f77::/64  ::/0                
    0     0 MASQUERADE  all      *      !docker0  fd00:dead:beef:c0::/80  ::/0                
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::b  fd4d:6169:6c63:6f77::b  tcp dpt:4190
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::b  fd4d:6169:6c63:6f77::b  tcp dpt:995
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::b  fd4d:6169:6c63:6f77::b  tcp dpt:993
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::b  fd4d:6169:6c63:6f77::b  tcp dpt:143
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::b  fd4d:6169:6c63:6f77::b  tcp dpt:110
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::f  fd4d:6169:6c63:6f77::f  tcp dpt:587
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::f  fd4d:6169:6c63:6f77::f  tcp dpt:465
    0     0 MASQUERADE  tcp      *      *       fd4d:6169:6c63:6f77::f  fd4d:6169:6c63:6f77::f  tcp dpt:25

Chain DOCKER (2 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 RETURN     all      br-mailcow *       ::/0                 ::/0                
    0     0 RETURN     all      docker0 *       ::/0                 ::/0                
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:4190 to:[fd4d:6169:6c63:6f77::b]:4190
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:995 to:[fd4d:6169:6c63:6f77::b]:995
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:993 to:[fd4d:6169:6c63:6f77::b]:993
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:143 to:[fd4d:6169:6c63:6f77::b]:143
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:110 to:[fd4d:6169:6c63:6f77::b]:110
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:587 to:[fd4d:6169:6c63:6f77::f]:587
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:465 to:[fd4d:6169:6c63:6f77::f]:465
    0     0 DNAT       tcp      !br-mailcow *       ::/0                 ::/0                 tcp dpt:25 to:[fd4d:6169:6c63:6f77::f]:25

DNS check:

104.18.32.7
172.64.155.249

[milkmaker]

THIS IS A AUTOMATED MESSAGE!

It seems your issue is not a bug. Therefore we highly advise you to get support!

You can get support either by:

• ordering a paid support contract at Servercow (Directly from the developers) or
• using the community forum (Based on volunteers! NO guaranteed answer) or
• using the Telegram support channel (Based on volunteers! NO guaranteed answer)

This issue will be closed. If you think your reported issue is not a support case feel free to comment above and if so the issue will reopened.

[DerLinkman]

Cannot reproduce it.