In this guide, you will learn how to change the default docker bridge network's subnet to **10.11.12.0/24** on Ubuntu

## Docker-engine's default options
Docker creates a bridge called docker0 with a default ip address of 172.17.0.1.

On Ubuntu the configuration file is located at:
```
/etc/default/docker
```

## Edit the docker-engine configuration file
If DOCKER_OPTS is alredy exist then add the following option:
```
--bip=10.11.12.1/24
```
So it will look like:
```
DOCKER_OPTS="--host=tcp://0.0.0.0:2376 --host=unix:///var/run/docker.sock --bip=10.11.12.1/24"
```

Otherwise, just add a new line:
```
DOCKER_OPTS="--bip=10.11.12.1/24
```

## Restart docker-engine
```
sudo service docker restart
```