When running:
docker network create --ipv6 b46
docker run --rm -ti \
--network name=b46,driver-opt=com.docker.network.endpoint.sysctls=net.ipv6.conf.IFNAME.disable_ipv6=1 \
busybox
IPv6 is enabled in the container and the network, so an IPv6 address
will be allocated for the endpoint.
But, when the sysctl is applied, the IPv6 address will be removed
from the interface ... so, no unsolicited neighbour advertisement
should be (or can be) sent and, the endpoint should not be treated
as dual-stack when selecting a gateway endpoint and, if it is
selected as the gateway endpoint, setting up an IPv6 route via the
network will fail.
So, if the IPv6 address disappears after sysctls have been applied,
release the address and remove it from the endpoint's config.
Signed-off-by: Rob Murray <rob.murray@docker.com>
