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

Hi

 ---- On Fri, 21 Feb 2025 13:31:53 +0000  Eugene Pereviazko <[email protected]> wrote --- 
 > 21.02.25 08:52, A FreeBSD User пише:
 > > 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).
 > 
 > Am I correct that you want your host to combine predefined host part 
 > (instead of eui64) with dynamically received prefix?
 > 
 > Like, set host part to ::DEAD:1 then receive 2001:db8:1234:4321::/64 
 > prefix from router and get your address of 2001:db8:1234:4321::DEAD:1?
 > 
 > Then rtadvd is not a tool for that. rtadvd is for advertising, not 
 > receiving advertisements.
 > 
 > If I'm not mistaken You should try dhcpcd from ports or packages, 
 > specifically "slaac token" verb, as I don't know of similar feature in 
 > base system.
 > 
 > > Linux has this feature since a while and I can not believe that FreeBSD lacks such a feature.
 > >
 > > Thank you very much in advance,
 
As Eugene said, you can use dhcpcd in ports with the slaac directive like so

interface bge0
   slaac token ::dead:beef

Then you get ::dead:beef appended to each autoconf address from the RA.
You could use ::1 for your token which should meet your needs as above.

Good luck!

Roy