why rtsold ?

Victor Sudakov vas at mpeks.tomsk.su
Tue Oct 9 00:34:15 UTC 2018


Alan Somers wrote:
> > > > > > When running FreeBSD as an IPv6 host im SLAAC mode, is
> > > > > > "rtsold_enable=YES" really necessary? I did not enable rtsold and
> > IPv6
> > > > > > still works fine only with
> > > > >
> > > > > rtsold is needed to write DNS server address from RDNSS RA option to
> > > > > /etc/resolv.conf
> > > > >
> > > > > man rtsold
> > > > > /-R
> > > >
> > > > On my test IPv6-only host, /etc/resolv.conf was successfully created
> > > > without any explicit "rtsold_enable=YES".
> > > >
> > > > --
> > > > Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
> > > > 2:5005/49 at fidonet http://vas.tomsk.ru/
> > > >
> > > Remember that DHCPv6 can provide DNS server and other information even
> > when
> > > SLAAC is used for address configuration. If it is, it is possible to run
> > > SLAAC without rtsold, but it may not prove stable as it is not possible
> > to
> >
> > The case is that my IPv6 lab (actually a number of FreeBSD hosts in
> > bhyve) does not have a DHCPv6 server. Still, the /etc/resolv.conf on
> > IPv6-only hosts is successfully populated from the router.  The latter
> > is running only rtadvd with the following config:
> >
> >
> > bridge0:rdnss="2001:470:20::2,2001:4860:4860::8888,2001:4860:4860::8844":dnssl="
> > sibptus.ru":
> >
> > Magick?
> >
> 
> Not at all.  rtsol will populate /etc/resolv.conf just fine.

I see.

As I come to think about it, I even don't know how to enable a DHCPv6
client. In my test IPv6-only host, I keep only the following in
rc.conf.local:

ifconfig_vtnet0=""
ifconfig_vtnet0_ipv6="inet6 accept_rtadv"
ipv6_privacy="YES"

> But it only does it once.  rtsold is needed in case router info
> changes, or your address times out.  -Alan

Now I understand, thank you.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
2:5005/49 at fidonet http://vas.tomsk.ru/


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