Use IPv6 networking
IPv6 is only supported on Docker daemons running on Linux hosts.
Create an IPv6 network
Using
docker network create
:$ docker network create --ipv6 ip6net
Using
docker network create
, specifying an IPv6 subnet:$ docker network create --ipv6 --subnet 2001:db8::/64 ip6net
Using a Docker Compose file:
networks: ip6net: enable_ipv6: true ipam: config: - subnet: 2001:db8::/64
You can now run containers that attach to the ip6net
network.
$ docker run --rm --network ip6net -p 80:80 traefik/whoami
This publishes port 80 on both IPv6 and IPv4. You can verify the IPv6 connection by running curl, connecting to port 80 on the IPv6 loopback address:
$ curl http://[::1]:80
Hostname: ea1cfde18196
IP: 127.0.0.1
IP: ::1
IP: 172.17.0.2
IP: 2001:db8::2
IP: fe80::42:acff:fe11:2
RemoteAddr: [2001:db8::1]:37574
GET / HTTP/1.1
Host: [::1]
User-Agent: curl/8.1.2
Accept: */*
Use IPv6 for the default bridge network
The following steps show you how to use IPv6 on the default bridge network.
Edit the Docker daemon configuration file, located at
/etc/docker/daemon.json
. Configure the following parameters:{ "ipv6": true, "fixed-cidr-v6": "2001:db8:1::/64" }
ipv6
enables IPv6 networking on the default network.fixed-cidr-v6
assigns a subnet to the default bridge network, enabling dynamic IPv6 address allocation.ip6tables
enables additional IPv6 packet filter rules, providing network isolation and port mapping. It is enabled by-default, but can be disabled.
Save the configuration file.
Restart the Docker daemon for your changes to take effect.
$ sudo systemctl restart docker
You can now run containers on the default bridge network.
$ docker run --rm -p 80:80 traefik/whoami
This publishes port 80 on both IPv6 and IPv4. You can verify the IPv6 connection by making a request to port 80 on the IPv6 loopback address:
$ curl http://[::1]:80
Hostname: ea1cfde18196
IP: 127.0.0.1
IP: ::1
IP: 172.17.0.2
IP: 2001:db8:1::242:ac12:2
IP: fe80::42:acff:fe12:2
RemoteAddr: [2001:db8:1::1]:35558
GET / HTTP/1.1
Host: [::1]
User-Agent: curl/8.1.2
Accept: */*
Dynamic IPv6 subnet allocation
If you don't explicitly configure subnets for user-defined networks,
using docker network create --subnet=<your-subnet>
,
those networks use the default address pools of the daemon as a fallback.
This also applies to networks created from a Docker Compose file,
with enable_ipv6
set to true
.
If no IPv6 pools are included in Docker Engine's default-address-pools
,
and no --subnet
option is given,
Unique Local Addresses (ULAs)
will be used when IPv6 is enabled. These /64
subnets include a 40-bit
Global ID based on the Docker Engine's randomly generated ID, to give a
high probability of uniqueness.
To use different pools of IPv6 subnets for dynamic address allocation, you must manually configure address pools of the daemon to include:
- The default IPv4 address pools
- One or more IPv6 pools of your own
The default address pool configuration is:
{
"default-address-pools": [
{ "base": "172.17.0.0/16", "size": 16 },
{ "base": "172.18.0.0/16", "size": 16 },
{ "base": "172.19.0.0/16", "size": 16 },
{ "base": "172.20.0.0/14", "size": 16 },
{ "base": "172.24.0.0/14", "size": 16 },
{ "base": "172.28.0.0/14", "size": 16 },
{ "base": "192.168.0.0/16", "size": 20 }
]
}
The following example shows a valid configuration with the default values and
an IPv6 pool. The IPv6 pool in the example provides up to 256 IPv6 subnets of
size /64
, from an IPv6 pool of prefix length /56
.
{
"default-address-pools": [
{ "base": "172.17.0.0/16", "size": 16 },
{ "base": "172.18.0.0/16", "size": 16 },
{ "base": "172.19.0.0/16", "size": 16 },
{ "base": "172.20.0.0/14", "size": 16 },
{ "base": "172.24.0.0/14", "size": 16 },
{ "base": "172.28.0.0/14", "size": 16 },
{ "base": "192.168.0.0/16", "size": 20 },
{ "base": "2001:db8::/56", "size": 64 }
]
}
Note
The address
2001:db8::
in this example is reserved for use in documentation. Replace it with a valid IPv6 network.The default IPv4 pools are from the private address range, similar to the default IPv6 ULA networks.
Docker in Docker
On a host using xtables
(legacy iptables
) instead of nftables
, kernel
module ip6_tables
must be loaded before an IPv6 Docker network can be created,
It is normally loaded automatically when Docker starts.
However, if you running Docker in Docker that is not based on a recent
version of the
official docker
image, you
may need to run modprobe ip6_tables
on your host. Alternatively, use daemon
option --ip6tables=false
to disable ip6tables
for the containerized Docker
Engine.