> On 5 Jul 2025, at 06:08, Geoff Steckel <g...@oat.com> wrote:
>
> Can anyone point me at a reference/discussion for ipv6 server addressing?
>
> rad(8) & slaacd(8) work well for clients.
>
> I have OpenBSD servers with IPv4 addresses including local DNS for them.
> I would like to allow naive clients to connect to them using IPv6.
> What addressing scheme might work well given ISP prefix changes?
>
> thanks
> Geoff Steckel
>
> I see three ways to do this. All have problems.
> 1) assign a fd00::/8 subnet for server access
> or
> 2) use the single (dynamic) global prefix everywhere
> or
> 3) advertise link-layer addresses for servers
> and
> 4) zeroconf isn't applicable and confuses things
>
I do option 1 and 2 at the same time, but I am not an expert in this space.
I statically assign fd00::/8 addresses to internal networks and services, but
also get a dynamic global prefix delegation from my ISP that gets assigned to
the same networks.
On my router I have this config:
dlg@router ~$ sudo cat /etc/hostname.lo1
inet6 alias fdXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX 128
up
dlg@router ~$ sudo cat /etc/hostname.re1
inet 192.168.0.1/24
inet6 alias fdXX:XXXX:XXXX:XXXX:1::1 64
group internal
dlg@router ~$ sudo cat /etc/hostname.re2
group external
inet autoconf
inet6 autoconf
dlg@router ~$ sudo cat /etc/dhcp6leased.conf
request prefix delegation on re2 for { re2/128 re1 }
dlg@router ~$ sudo cat /etc/rad.conf
interface re1 {
auto prefix
dns {
nameserver fdXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX
}
}
I dont know if this is normal, but I only get link local addresses with inet6
autoconf on the link to my ISP. However, I get a globally routable prefix with
dhcp6, so I assign one of the IPs out of that range to the external link on my
router to make it easier to talk to the internet.
unbound listens on the lo1 IP. This let me choose if I wanted to use fd00::/8,
or delegate a global prefix on the internal network, or both, and have the
nameserver reachable from any host on those networks because of their default
route.
I keep meaning to try and hack rad(8) up to see if I can set "router
preference” on a per prefix basis. If I’m using both fd00 and global addresses
on a net, I would like to prefer the global addresses. I haven’t actually
tested if this is actually useful or meaningful though.
Dlg
