[Dnsmasq-discuss] Quicker IPv6 connectivity recovery when using ra-stateless mode

[Toke Høiland-Jørgensen]

So I've been noticing that when resuming my laptop from suspend (and
reconnecting to the WiFi network), I will get IPv4 connectivity a lot
sooner than IPv6. I'm using dnsmasq in ra-stateless mode.

Looking at tcpdump output, it seems that my laptop will send a DHCP
solicit message (for both IPv4 and IPv6) immediately when the interface
connects to the WiFi, and it does get an IPv6 reply from dnsmasq. But it
takes a while before a router advertisement arrives, so there will be no
default route installed on the laptop.

Provided I'm interpreting what is happening correctly, would it be
possible to have dnsmasq trigger a router advertisement on an interface
whenever it replies to DHCP requests? Not sure if the RA spec allows
unicasting advertisements; if it does, unicasting it to the host that
asks for DHCP would be a way to cut down on multicast traffic. But
simply sending an additional multicast RA would also work, I suppose.

-Toke