<!--[metadata]> +++ draft=true title = "Tools and Examples" keywords = ["docker, bridge, docker0, network"] [menu.main] parent = "smn_networking_def" +++ <![end-metadata]--> <!--[metadata]> We may want to add it back in later under another form. Labeled DRAFT for now. Won't be built. <![end-metadata]--> # Quick guide to the options Here is a quick list of the networking-related Docker command-line options, in case it helps you find the section below that you are looking for. Some networking command-line options can only be supplied to the Docker server when it starts up, and cannot be changed once it is running: - `-b BRIDGE` or `--bridge=BRIDGE` -- see [Building your own bridge](#bridge-building) - `--bip=CIDR` -- see [Customizing docker0](#docker0) - `--default-gateway=IP_ADDRESS` -- see [How Docker networks a container](#container-networking) - `--default-gateway-v6=IP_ADDRESS` -- see [IPv6](#ipv6) - `--fixed-cidr` -- see [Customizing docker0](#docker0) - `--fixed-cidr-v6` -- see [IPv6](#ipv6) - `-H SOCKET...` or `--host=SOCKET...` -- This might sound like it would affect container networking, but it actually faces in the other direction: it tells the Docker server over what channels it should be willing to receive commands like "run container" and "stop container." - `--icc=true|false` -- see [Communication between containers](#between-containers) - `--ip=IP_ADDRESS` -- see [Binding container ports](#binding-ports) - `--ipv6=true|false` -- see [IPv6](#ipv6) - `--ip-forward=true|false` -- see [Communication between containers and the wider world](#the-world) - `--iptables=true|false` -- see [Communication between containers](#between-containers) - `--mtu=BYTES` -- see [Customizing docker0](#docker0) - `--userland-proxy=true|false` -- see [Binding container ports](#binding-ports) There are three networking options that can be supplied either at startup or when `docker run` is invoked. When provided at startup, set the default value that `docker run` will later use if the options are not specified: - `--dns=IP_ADDRESS...` -- see [Configuring DNS](#dns) - `--dns-search=DOMAIN...` -- see [Configuring DNS](#dns) - `--dns-opt=OPTION...` -- see [Configuring DNS](#dns) Finally, several networking options can only be provided when calling `docker run` because they specify something specific to one container: - `-h HOSTNAME` or `--hostname=HOSTNAME` -- see [Configuring DNS](#dns) and [How Docker networks a container](#container-networking) - `--link=CONTAINER_NAME_or_ID:ALIAS` -- see [Configuring DNS](#dns) and [Communication between containers](#between-containers) - `--net=bridge|none|container:NAME_or_ID|host` -- see [How Docker networks a container](#container-networking) - `--mac-address=MACADDRESS...` -- see [How Docker networks a container](#container-networking) - `-p SPEC` or `--publish=SPEC` -- see [Binding container ports](#binding-ports) - `-P` or `--publish-all=true|false` -- see [Binding container ports](#binding-ports) To supply networking options to the Docker server at startup, use the `DOCKER_OPTS` variable in the Docker upstart configuration file. For Ubuntu, edit the variable in `/etc/default/docker` or `/etc/sysconfig/docker` for CentOS. The following example illustrates how to configure Docker on Ubuntu to recognize a newly built bridge. Edit the `/etc/default/docker` file: ``` $ echo 'DOCKER_OPTS="-b=bridge0"' >> /etc/default/docker ``` Then restart the Docker server. ``` $ sudo service docker start ``` For additional information on bridges, see [building your own bridge](#building-your-own-bridge) later on this page.