Speaker crashloops on machine with IPv6 disabled

[danderson]

The NDP announcer causes a hard failure if there is no link-local IPv6 address on the listening interface. This notably breaks RHEL7 and OEL7, because they're quite old and apparently have IPv6 hard-disabled in the kernel, so even link-local autoconfig doesn't happen.

[jpiper]

Works for me!

[danderson]

Yeah, discussion in slack concluded that this is specific to one environment, where network/sys ops completely disabled IPv6 for some reason.

I still want speaker to fail gracefully if one of the protocol families doesn't work.

[Russell-IO]

@danderson I think that I'm hitting this bug, out networking team disable IPv6 as Standard on all hosts, and it doesn't seem to advertise the root, if I enable IPv6, it works