# Benutzerdefinierte Docker-Netzwerkkonfiguration – Container-zu-Container-Kommunikation

**URL:** <https://meta.discourse.org/t/custom-docker-network-configuration-container-to-container-comms/84654>\
**Category:** Self-hosting\
**Created:** [5. April 2018 um 15:52 UTC](https://meta.discourse.org/t/custom-docker-network-configuration-container-to-container-comms/84654 "2018-04-05T15:52:23Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![gaiterjones](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/gaiterjones/32/120146_2.png) [@gaiterjones](https://meta.discourse.org/u/gaiterjones)\
**Post date:** [5. April 2018 um 15:52 UTC](https://meta.discourse.org/t/custom-docker-network-configuration-container-to-container-comms/84654/1 "2018-04-05T15:52:23Z")

</div>

I am installing Docker on a host where all applications are already containerised including the main smtp server.

When I try and relay mail from discourse to this smtp server it fails because the server cannot do a reverse lookup on the Discourse server IP. This works fine with my other containers because using docker compose I am allowing access to the mail server docker network using for example something like

```
services:
  php-apache:
     networks:
            - mail_server

networks:
    mail_server:
      external: true

```

How can I achieve this with Discourse so that Discourse service container and the mail server service container can communicate with each other directly?

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_[View the full topic](https://meta.discourse.org/t/custom-docker-network-configuration-container-to-container-comms/84654)._