1

My host has ipv6 which works fine. But my containers cant connect out on ipv6.

Docker version 18.03.1-ce, build 9ee9f40

/etc/network/interfaces (host)

iface eth0 inet6 static
address 2001:xxxx:5000:20::0010
netmask 64
gateway 2001:xxxx:5000:20::1

/etc/docker/daemon.json

{
    "ipv6": true,
    "fixed-cidr-v6": "2001:xxxx:5000:20::/64",
    "default-gateway-v6": "2001:xxxx:5000:20::1"
}

sysctl (host)

net.ipv6.conf.default.forwarding = 1
net.ipv6.conf.all.forwarding=1

docker run -it alpine ash -c "ip -6 addr show dev eth0; ip -6 route show; ping6 google.com"

259: eth0@if260: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 state UP 
    inet6 2001:xxxx:5000:20::242:ac11:2/64 scope global flags 02 
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:2/64 scope link tentative 
       valid_lft forever preferred_lft forever

2001:xxxx:5000:20::/64 dev eth0  metric 256 
fe80::/64 dev eth0  metric 256 
default via 2001:xxxx:5000:20::1 dev eth0  metric 1024 
ff00::/8 dev eth0  metric 256 

PING google.com (2a00:1450:4009:801::200e): 56 data bytes

Ping just hangs

0

Try passing --network host to your docker run command. This will give your container access to all interfaces on the host.

From docker docs: Note: --network="host" gives the container full access to local system services such as D-bus and is therefore considered insecure.

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  • 1
    It's a bit of a hack. I want docker to work as it's supposed to. In this scenario, to get an individual ipv6 address, it would need to be configured inside the container. – user37914 Jul 10 '18 at 18:31
0

Change the /64 to an /80.

/etc/docker/daemon.json

{
    "ipv6": true,
    "fixed-cidr-v6": "2001:xxxx:5000:20::/80",
}

You may need to switch on

sysctl -w net.ipv6.conf.all.proxy_ndp=1
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