[ltp] dhcp problem

Johnny Casey linux-thinkpad@linux-thinkpad.org
Tue, 02 Dec 2003 17:43:48 -0600

André Wyrwa wrote:
> Hei Pekka,
> asutko Oulussa?
>>>the search entry is correct now, since i included the supersede entry in
>>>the config file above. However, the server entries are still crap and i
>>>still don't know where they come from.
>>	From your DHCP server?
> Probably.

 From what follows it looks like you are using the ISC DHCP client 
(dhclient), either version 2.xx or 3.0.

On most systems where this is used most of the work is done via bash 
scripts.  Particularly dhclient-script.  This script might be located 
under /etc or in /sbin.  One of the chores of the scrip involves senting 
up "/etc/resolv.conf".  It probably does this in the "make_resolv_conf" 

Additionally the script will call other scripts or hooks to do what ever 
you want it to do.  For instance, the dhclient-script calls enter and 
exit scripts.  On Debian and probably others these are called 
dhclient-enter-hooks and dhclient-exit-hooks, imaginative isn't it. 
These scripts can usually be dropped in /etc or /etc/dhcp3, however you 
really should look through the dhclient-script itself to be sure.

If you are still having problems, you can make use of the 
dhclient-exit-hooks script to write your own "/etc/resolv.conf".

>>>prepend domain-name-servers,;
>>	Here you specify and as your DNS servers.
> Which are the correct ones, but not .

Rather than use prepend, you could use "supersede" to force a particular 
set of values rather than use the scripts as above.

>>>request subnet-mask, broadcast-address, time-offset, routers,
>>>       domain-name, domain-name-servers, host-name;
>>>require subnet-mask, domain-name-servers;
>>	You ask for domain-name and domain-name-servers there. If that
>>	is not what you want, don't do it. Replace your configuration
>>	with something like this:
>>interface "eth0" {
>>send host-name "froschkoenig";
>>request subnet-mask, broadcast-address, time-offset, routers,
>>        host-name;
>>require subnet-mask;
> Yes, but as stated in one of my former mails, I tried that already.
> Without success, i still got the obsolete entries in dhclient.leases.
> However, I'll try again and also give tcpdump a try.
> Thx a lot to all who replied. It really seems to be a problem with the
> airbase, not with my installation.
> Andre.

dhclient.conf(5) is your friend.