Describe IPv6-only network config

Signed-off-by: Rob Murray <[email protected]>

Author: robmry

content/manuals/engine/network/_index.md

@@ -144,6 +144,14 @@ direct routing to containers, see
 
 ## IP address and hostname
 
+When creating a network, IPv4 address allocation is enabled by default, it
+can be disabled using `--ipv4=false`. IPv6 address allocation can be enabled
+using `--ipv6`.
+
+```console
+$ docker network create --ipv6 --ipv4=false v6net
+```
+
 By default, the container gets an IP address for every Docker network it attaches to.
 A container receives an IP address out of the IP subnet of the network.
 The Docker daemon performs dynamic subnetting and IP address allocation for containers.

content/manuals/engine/network/drivers/bridge.md

@@ -232,6 +232,17 @@ $ docker network create --ipv6 --subnet 2001:db8:1234::/64 my-net
 If you do not provide a `--subnet` option, a Unique Local Address (ULA) prefix
 will be chosen automatically.
 
+## IPv6-only bridge networks
+
+To skip IPv4 address configuration on the bridge and in its containers, create
+the network with option `--ipv4=false`, and enable IPv6 using `--ipv6`.
+
+```console
+$ docker network create --ipv6 --ipv4=false v6net
+```
+
+IPv4 address configuration cannot be disabled in the default bridge network.
+
 ## Use the default bridge network
 
 The default `bridge` network is considered a legacy detail of Docker and is not