New install: Could not connect to Redis at redis:6379: Host is unreachable

otaehryn

I installed mailcow on Centos 8 host running on ESX 6.7. I forwared ports, sorted DNS records to external IP.
I set selinux to permissive
I also disabled IPV6 because currently not present (need to sort out with ISP) using official guide.

After docker-compose up -d I get 502 error and when i check logs i get:
Could not connect to Redis at redis:6379: Host is unreachable

Any ideas? How do I troubleshoot this?

Also I yesterday I had same error when I restored my test mailcow from Hetzner to esx but I attributed this to hostname, ports, DNS not being taken care off.

diekuh

There is no Docker on CentOS 8.

Furthermore:

otaehryn

I have a test mailcow running on centos 8 on Hetzner that is working. Trying Centos7 now.

diekuh

It starts, but it will not work. There is a reason there are no packages for C8. 🙂

otaehryn

diekuh Ok, got Centos 7 setup up, seems to be working.
There is a catch: if you disable IPV6 as per guide:

Create data/conf/postfix/extra.cf and set smtp_address_preference to ipv4:

smtp_address_preference = ipv4

docker-compose will try to bring up two postfixes. After I added smtp_address_preference = ipv4 to main.cf it worked.
Also Centos 7 minimal had postfix so I had to disable that.

diekuh

That’s not related. Something else is broken then.

docker-compose does not care about the Postfix instances. 🙂 Better run down und up -d again and check what it does.

otaehryn

Thank you for help, everything seems to be working now.
The problem with postfix was because Centos7 minimal has posftix on by default and postfix on docker couldn’t start.

MAGIC

otaehryn
The best would be to remove the postfix install from your CentOS then to avoid problem when you upgrade your system