dhclient and resolv.conf.sav

[Brooks Davis]

On Fri, Jul 11, 2008 at 08:32:49AM +0200, Willy Offermans wrote:
> Dear FreeBSD friends,
> 
> Is this behavior, related to dhclient and /etc/resolv.conf.sav, FreeBSD
> specific or is it a general feature of dhclient? I might have a use for
> it on my debian linux laptop.

We picked it up from openbsd when we took their client (which is derived from
an early ISC client).  If it's not in the stock isc dhclient-script adding it
would be trivial.

-- Brooks

> On Thu, Jul 10, 2008 at 11:57:41AM -0500, Brooks Davis wrote:
> > On Thu, Jul 10, 2008 at 10:52:35AM +0200, Patrick M. Hausen wrote:
> > > Hello,
> > > 
> > > we have been bitten by something that obvoiusly
> > > is a feature, not a bug, but I do not quite understand
> > > the intentions and reasoning behind it.
> > > 
> > > I have a host with manual interface and resolver configuration
> > > and an additional interface that should get it's IP address
> > > via DHCP. But only it's IP address and netmask, nothing else.
> > > 
> > > The DHCP server used hands out only IP addresses/netmasks,
> > > no domain-name-servers, domain-name, etc. configured.
> > > 
> > > Yet, if there happens to exist a /etc/resolv.conf.sav file,
> > > every renewal of the lease by dhclient overwrites the contents
> > > of /etc/resolv.conf with those of resolv.conf.sav.
> > > 
> > > In my particular case the .sav file contained an internal
> > > nameserver that was used when I initially set up the host
> > > in the lab. This entry was of no use to the server after
> > > it had been deployed in our datacenter.
> > > 
> > > Can anyone shed some light on the intended mechanism?
> > > Studying the dhclient-script was not too helpful, either.
> > 
> > I suspect the theory is that you can have a static resolv.conf around
> > that gets installed when there isn't anything else to use.  In practice,
> > I think it mostly causes problems.  I'm somewhat tempted to remove the
> > creation of the file and add something like a resolv.conf.default in
> > it's place.
> > 
> > -- Brooks
> 
> 
> 
> -- 
> Met vriendelijke groeten,
> With kind regards,
> Mit freundlichen Gruessen,
> De jrus wah,
> 
> Willy
> 
> *************************************
> Dr. W.K. Offermans
> CAT Postdoctoral Fellow
> CAT Catalytic Center
> Institut f?r Technische und Makromolekulare Chemie
> RWTH Aachen
> Worringerweg 1, Raum 38C-150
> D-52074 Aachen, Germany
> Phone:  +49 241 80 28592
> Home:   +31 45 544 49 44
> Mobile: +31 653 27 16 23
> e-mail: Willy at Offermans.Rompen.nl
> e-mail: Willy.Offermans at CatalyticCenter.RWTH-Aachen.de
> 
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