Re: rtadvd(8) How to IPv6 tokenize interface identifier

Hi,

> On 21 Feb 2025, at 06:52, A FreeBSD User <freebsd@walstatt-de.de> wrote:
> 
> Hello,
> 
> Linux (especially OpenWRT we use) knows about a concept named "IPv6 tokenized interface
> identifier". The concept is self explanatory, a interface/router obtains a propagated prefix
> and the concept allows the explicit definition of the host portion.
> 
> I haven't managed to accomplish such a behaviour using FreeBSD's rtadvd(8) daemon. I guess
> this task is subject of and performed through the rtadvd.conf(5) configuration file, but I
> haven't managed yet to accomplish such a task (to speak simple: I'd like to have a router of a
> subnet always at IPv6 Network PREFIX:0:0:0:1).

Isn’t sufficient just to give the router a static IPv6 address? That’s what we do here.

> The only config tag I can imagine is responsible for what I'd like to achive is the "addr" tag
> mentioned in rtadvd.conf(5), but whatever I fill this tag with - the desired effect is never
> achived (i.e addr="::0.0.0.1"). My "FreeBSD homebrewn" router has several networks, attached
> to vlan. Each interface is subject of an ULA prefix and an IPv6 prefix provided by our ISP. It
> is possible to pin the ULA toward the desired address, like addr="fd50:c450::1", but then the
> ISP provided prefix seems not to be set properly or is completely absent. Omitting "addr="
> provides the interface with ULA prefix and ISP prefix - but obviously with the randomly
> generated 64bit host portion.
> 
> Playing around with mutually suitable tags, like "pinfoflags", "raflags" or "rtflags" and
> having probed almost every possible combination (with or without some sense), it seems
> impossible to provide a) both ULA and ISP prefix pin the host portion to a desired 64bit
> address, like "PREFIX::1".
> 
> I do not exclude that I'm possibly incapable of comprehension the manpage (the language is and
> the deeper semantics seem then to be hidden for me). So, if there is a clear expalanation how
> to achive the desired, please point me towards it (thanks in advance!).
> 
> Linux has this feature since a while and I can not believe that FreeBSD lacks such a feature.
> 
> Thank you very much in advance,
> 
> O. Hartmann
> 
> 
> -- 
> 
> A FreeBSD user

--
Bob Bishop
rb@gid.co.uk