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

Am Fri, 21 Feb 2025 10:44:12 +0000
Bob Bishop <rb@gid.co.uk> schrieb:

> 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.

Hello.

The router itself has on all inbound NICs static ULAs, ending as desired on "fc:/7-PREFIX::1".
Using KAME dhcp6c, software from 2008(!), with a configuration obatined for delegating a
prefix, each NIC - except tun0 for whatever reason - gets a prefix, the inbound NICs then seem
to get a EUI64 generated IPv6 (although I sepcified "privacy", but this seems to be
ignored, sadly ...). 
 
> 
> > 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
> 
> 
> 
> 



-- 

A FreeBSD user