# Using Docker network and the extra_hosts property > Resolve host aliases inside Docker containers! Learn to use docker network and the extra_hosts property in docker compose to seamlessly connect your services. ---  **TL;DR** This article explains why one Docker container can't reach another unless both run on the same Docker network, walking through creating a shared network, finding its gateway IP with `docker network inspect`, and connecting a second container to it via `compose.yaml`. It also shows how to reuse a host-side hosts-file alias inside a container with the `extra_hosts` property. When you're running a Docker container on a different network than the standard one (called `bridge`) and **you wish to run a second container that needs to access the first container, you need to run the second container on the same network.** Let's say, you're running a MySQL database on a network called `my_network` and you wish to be able start a second container like [phpMyAdmin](https://hub.docker.com/_/phpmyadmin) (see [Using Adminer, pgadmin or phpmyadmin to access your Docker database container](/blog/docker-adminer-pgadmin-phpmyadmin)) and get access to the database, then you need to use the `--network` CLI option when running the second container using `docker run`. Now, imagine the first container is a web application and the second container should be able to access its web page and, too, reuse the same alias? ## The two-line fix Here is the whole answer, at the top of the article rather than at the end. Add `extra_hosts` to the service that needs to reach your host alias: **compose.yaml** ```yaml services: my_second_container: build: context: . networks: - my_network //highlight-next-line extra_hosts: //highlight-next-line - "my_site.local:172.20.0.1" networks: my_network: external: true ``` Jump into the container and look at what Docker did with it: ```bash $ docker compose run -it --rm --entrypoint /bin/sh my_second_container $ cat /etc/hosts 127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.20.0.1 my_site.local $ curl http://my_site.local:8080 ``` ```html