Docker Networking (Null Network, None Network)
none network in docker means when you don't want any network interface for your container. If you want to completely disable the networking on a container, you can use the --network none flag when starting the container. Within the container, only the loopback device is created.
Create a container with network type as 'null'
gaurav@learning-ocean:~$ docker container run -it --network none ubuntu:14.04 bash
Now check the network configuration of this container with ifconfig command-
root@0e26891303d0:/# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@0e26891303d0:/#
So a null type of network is used when the container is not a part of any network and is isolated in all aspects.