Re: [RFC] Automated generation of /etc/resolv.conf from the rc.d script

On Monday 14 April 2008 11:44:13 am Eygene Ryabinkin wrote:
> Poul-Henning, good day.
>
> Fri, Dec 14, 2007 at 02:07:00PM +0300, Eygene Ryabinkin wrote:
> > Fri, Dec 14, 2007 at 10:57:38AM +0000, Poul-Henning Kamp wrote:
> > > In message <dEZnki0Fi32EvMrDEnqcgDeNQSc_at_Bbw9J2Iynx0QjNoWuQ4YSitYS3A>, 
Eygene Ryabinkin writes:
> > > >> It should be possible to run a local named even when we run DHCP,
> > > >> and it shuld be an option, to have it automatically forward to the
> > > >> DNS servers we learn from DHCP.
> > > >
> > > >This can be achieved with the script /etc/dhclient-exit-hooks that
> > > >will create the file with named 'forwarders' clause [...]
> > >
> > > Yes, I know that, but I would like to see it controllable from rc.conf
> > > like the rest of our network configuration.
> >
> > OK, since running local DNS instance is a neat idea, I will try to
> > draft the modifications for the dhclient-exit-hooks, as I described
> > in the previous mail.
>
> At last, I did the needed modifications: patches against 7.0 from
> yesterday, April 13th, are attached.  The first one enables the
> creation of /etc/resolv.conf from rc.conf variables and the second
> brings the named forwarders rewriting using values obtained via
> DHCP.  I had touched dhclient-script, but it was really needed,
> because it is not good to have simular functionality in /etc/rc.d/resolv
> and in the dhclient-script.
>
> I decided not to cope with modifications of /etc/namedb/named.conf,
> but rather to create other file, /etc/namedb/named.forwarders.conf,
> that should be included from the main configuration.
>
> I am living for two days with this configuration (DHCP + local named
> instance) and no problems were spotted yet.
>
> Testing and feedback are more than welcome.

You can already override the domain name and DNS servers (including either 
overriding, providing a default, or prepending or appending to the list) via 
setings in /etc/dhclient.conf, so I don't think new rc.conf variables for 
that would be warranted.  Updating named.conf to forward is a neat idea.  
Howver, on my laptop on HEAD I've ended up just running nscd instead of a 
local DNS server and doing a 'nscd -I hosts' when I get a new lease to flush 
the host cache.  When I get to my laptop I'll post my bits of 
dhclient-exit-hooks and dhclient.conf to make this work.

-- 
John Baldwin