> Note that the MTU is not advertised for IPV6_NATIVE and IPV6_MANUAL either.

I didn't notice that, thanks for pointing it out.

> The default MTU will be the same as the link (1500 for ethernet), unless a previous advertisement included an MTU value.

Awesome.

> Please take a look at the entire diff. I added this line in case some was going to ask why I moved the case IPV6_NATIVE_DHCP a few lines down.

I understand what the change is doing. What I don't understand is how the length of the delegated prefix relates to (not) advertising a MTU.