Docker, poste.io and 25 port

For the last few months we (wormsoft.ru) are creating several integrations with email systems for our clients. And the one of the problem deserve to be explained in this blog. We are using poste.io for create email services and, we couldn’t to manage with fact – docker didn’t open 25 port for our app.

Our docker-compose.yml was look like this:

  mailserver:                            
    image: analogic/poste.io                             
    ports:                               
      - 110:110                          
      - 143:143                          
      - 465:465                          
      - 587:587                          
      - 993:993                          
      - 25:25                       
      - 995:995                                                 

No matter how we try – Docker was stable – 25 port was close. But inside the container 25 port was open and ready for connections! We haven’t found the final reason of this, but it could be solved by changing port configuration in docker-compose.yml from 25:25 to 0025:0025. Whats was this? I don’t know. If you know, please, tell me:) But after this change every thing started work fine!

And now, out docker-compose.yml file looks like this:

  mailserver:                            
    image: analogic/poste.io                             
    ports:                               
      - 110:110                          
      - 143:143                          
      - 465:465                          
      - 587:587                          
      - 993:993                          
      - 0025:0025                       
      - 995:995                                                 

If I find out the reason of this, I’ll write it here. Have a nice day!