Skip site navigation (1)Skip section navigation (2)
Date:      Sun, 09 Mar 2003 10:15:40 -0800 (PST)
From:      =?ISO-8859-1?Q?Mikko_Ty=F6l=E4j=E4rvi?= <mbsd@pacbell.net>
To:        David Kelly <dkelly@HiWAAY.net>
Cc:        FreeBSD-Questions@FreeBSD.org
Subject:   Re: DHCP Server "learning" name servers since server itself is dhcp'd??
Message-ID:  <20030309100615.Y6008-100000@atlas.home>
In-Reply-To: <200303082234.19615.dkelly@HiWAAY.net>

next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 8 Mar 2003, David Kelly wrote:

> On Saturday 08 March 2003 12:32 pm, Mikko Työläjärvi wrote:
> >
> > It is more elegant in perl, but dhclient-enter-hooks is a
> > shellscript, so it felt easier to just add it there.
>
> /etc/dhclient-enter-hooks needs to be created in any case if you wish to
> use named else it will write an /etc/resolv.conf containing the values
> given by the DHCP server. Something like this is all it takes to keep
> it from changing your resolv.conf:
>
> #!/bin/sh
> make_resolv_conf() {
> }

I know.

> Naturally, one could expand my null'ed make_resolv_conf() to 1) verify
> DNS servers have changed, and 2) write them in /etc/namedb/named.conf,
> then 3) "ndc restart"

That is what I'm doing, as would have been evident from the part of
the mail you snipped...

I also update time servers, web proxies, time zone, smtp forwarder
and a few other things.

> My ISP has done something in the past year or so that dhclient thinks
> each and every lease renewal is practically a new lease.
> /etc/resolv.conf gets (actually, only "attempted" now) written on each
> renewal. /var/log/messages gets flooded with this:
>
> Mar  8 21:14:29 grumpy dhclient: New Network Number: 24.214.34.0
> Mar  8 21:14:29 grumpy dhclient: New Broadcast Address: 24.214.34.255

After having been confronted with a number of different more or less
broken DHCP setups, I have come to the conclusion that the information
seldom is directly usable.  Instead one has to do pattern matching on
the data from the server and map to a collection of known settings for
known locations, plus a sanity-checking fallback case for new, untried
locations.

     $.02,
     /Mikko


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20030309100615.Y6008-100000>