SMTP behind nginx reverse-proxy (docker)

tdon

Hello,

I’m new to the community. First of all thank you for this great tool! I’ve just began to use it and its fantastic.
Nevertheless I’ve got problem with some configuration and it would be nice if some could help me:

Setup:
I’m using mailcow and some other tools (like seafile) behind a reverse-proxy (I use: https://hub.docker.com/r/jwilder/nginx-proxy). This means all tools are separate containers and share a common docker network (lets call it “nginx-network”), which connects them to the nginx-proxy and therefore establishes the connection to the Internet:

Internet <–> nginx-proxy (docker-container, nginx-network) <–> mailcow (docker-containter, nginx-network)
Internet <–> nginx-proxy (docker-container, nginx-network) <–> seafile (docker-container, nginx-network)

Problem:
Using mailcow to send mails per smtp from one of the other containers/tools on the “nginx-network”.

Example:
If I try to access port 465 of mailcow behind the nginx-proxy from one of the containers on the nginx-network mailcow doesn’t allow me to connect (example: use mailcow smtp to send mails from seafile container). Connecting from the outside (internet) through the nginx-proxy on port 465 works perfectly. I assume I somehow need to tell mailcow to allow smtp requests from the internal “nginx-network”. But I have no idea how to do this.

It would be nice if anyone has an idea? Thanks!

D4niel

I’m not sure if you’re using the reverse proxy correctly.

tdon Connecting from the outside (internet) through the nginx-proxy on port 465 works perfectly

Why would you place your postfix container behind a reverse proxy? You only need to place the mailcow nginx container behind a reverse proxy as the reverse proxy only handles web traffic. And I don’t think you placed it behind the reverse proxy since it probably wouldn’t work at all right now.

Just create a new network and assign it to the postfix container (with your domain as an network alias) and the container you want to send mails from. Then you can send mails through {MAILCOW_HOSTNAME}:465.

AllgaeuerBraunvie

did you use the right “hostname” within that network? it’s most likely just “postfix-mailcow” and should be resolved by docker to the right ip automatically.

tdon

AllgaeuerBraunvie Thanks! that was the solution! I somehow messed up the hostname.

tdon

D4niel Sorry for the undetailed description above. I did it exactly like you described. I just only have the mailcow nginx container behind the reverse proxy. Thanks for your help!