docker0#

MCR creates and configures the host system with the docker0 virtual network interface, an ethernet bridge through which all traffic between MCR and the container moves. MCR uses docker0 to handle all container routing. You can specify an alternative network interface when you start the container.

MCR allocates IP addresses from the docker0 configurable IP range to the containers that connect to docker0. The default IP range, or subnet, for docker0 is 172.17.0.0/16.

You can change the docker0 subnet in /etc/docker/daemon.json using the settings in the following table. Be aware that you must restart the docker.service to activate your daemon.json file edits.

Parameter

Description

default-address-pools

Modify the first pool in default-address-pools.

Caution

By default, MCR assigns the second pool to docker_gwbridge. If you modify the first pool such that the size does not match the base netmask, it can affect docker_gwbridge.

{
   "default-address-pools": [
         {"base":"172.17.0.0/16","size":16}, <-- Modify this value
         {"base":"172.18.0.0/16","size":16},
         {"base":"172.19.0.0/16","size":16},
         {"base":"172.20.0.0/16","size":16},
         {"base":"172.21.0.0/16","size":16},
         {"base":"172.22.0.0/16","size":16},
         {"base":"172.23.0.0/16","size":16},
         {"base":"172.24.0.0/16","size":16},
         {"base":"172.25.0.0/16","size":16},
         {"base":"172.26.0.0/16","size":16},
         {"base":"172.27.0.0/16","size":16},
         {"base":"172.28.0.0/16","size":16},
         {"base":"172.29.0.0/16","size":16},
         {"base":"172.30.0.0/16","size":16},
         {"base":"192.168.0.0/16","size":20}
   ]
}

fixed-cidr

Configures a CIDR range.

Customize the subnet for docker0 using standard CIDR notation. The default subnet is 172.17.0.0/16, the network gateway is 172.17.0.1, and MCR allocates IPs 172.17.0.2 - 172.17.255.254 for your containers.

{
  "fixed-cidr": "172.17.0.0/16",
}

bip

Configures a gateway IP address and CIDR netmask of the docker0 network.

Customize the subnet for docker0 using the <gateway IP>/<CIDR netmask> notation. The default subnet is 172.17.0.0/16, the network gateway is 172.17.0.1, and MCR allocates IPs 172.17.0.2 - 172.17.255.254 for your containers.

{
  "bip": "172.17.0.0/16",
}