Unable to add IPv6 address to dummy interface inside the container

General Discussions
#1

Hi,

I’m building a container that uses IPv6. Base IPv6 connectivity is working fine, but the application I’m using also needs a dummy interface with an IPv6 (and also IPv4) address on it:

ip link add dummy0 type dummy

ip a a 192.168.13.1/32 dev dummy0

works fine.

But when I try to add IPv6 address:

ip a a fd12:3456:7891:a::1/128 dev dummy0
ip: RTNETLINK answers: Permission denied

I tried with --privileged but that doesn’t change anything. Any idea how to add an IPv6 address to a dummy interface inside the container? (I have also tried ‘public IPv6’, that doesn’t work either)

docker --version
Docker version 19.03.4, build 9013bf583a
#2

Replying to myself here, for future reference.

It looks like it’s just not possible to use the ‘dummy’ type interface and assign it an IPv6 address, so I have resorted to using ‘lo’ interface and adding the addresses there.

#3

Hi, if you add --sysctl net.ipv6.conf.all.disable_ipv6=0 to your docker run command you’ll be able to achieve what you were trying to do!