Is using `net.ipv6.conf.all.forwarding` correct?

[containernetworking]

Is using `net.ipv6.conf.all.forwarding` correct?

[squeed]

So, I did some investigation. Fortunately, we're mostly OK.

The IsRouter flag is set on Neighbor Advertisement messages - it does not cause Router Advertisement messages to be sent. This is good.

However, administrators will probably want to set accept_ra to 2 on their uplink interface. We should probably not set this by default, but it will be necessary for hosts using SLAAC for their uplink.

[squeed]

Next TODO: can we get away with setting forward only on the host-side interface?

[squeed]

Another interesting discovery: If you want to do Masquerading (i know, i know), then net.ipv6.conf.all.forwarding must be 1. Even enabling it on every interface, but not for all, isn't sufficient.

[squeed]

Closing this; there's nothing to do here.