ipv6 distribute an ula prefix without an router

I have a network which has no ipv6 connectivity to the internet. But I'd like to play a little with private networking.

So I want to use ULAs for my devices and automatically distribute the prefix.

I know that ipv6 uses router advertisement to do so. But (hence the name...) it advertises a router, too. In my case using dnsmasq it's the address of the server running it. So it ends up in my clients as a default route.

Since I don't have a router and don't want my clients to have a default route is there a way to dynamically assign ula prefixes without a router?

And even more "advanced": Is there a way to use dhcpv6 without a router?

Solution 1:

No, Router Advertisements means the RA sender is willing to be a router, along with prefix information. And you need a router to do anything useful with IP.

Hosts will send Router Solicitations out. The Router Advertisement they get back they will assume is from a router, and use its link local address as a gateway. Benefit of this, discovering a gateway is inherent to neighbor discovery, automatic, and requires no DHCP.

Only allow RAs to be sent from hosts you wish to be routers. If you did not want dnsmasq to send RAs, disable that. Enable RAs on your router. If you aren't ready for an IPv6 implementation in production yet, practice in a test environment.

For your address plan, get a globally routable prefix from your ISP, or generate a unique ULA prefix to use. Note that ULA cannot get you to the internet.