How to specify a default nameserver in /etc/resolv.con

libregeek · 11-18-2005, 12:08 AM

Hello all,
The Internet connection in my network is accessed through a Fedora Core 3. This machine acts as the router and as a development machine in the network. One of the ethernet interface is configured to assign the IP address through DHCP (of the ISP). The contents in the /etc/resolv.conf is automatically assigned by the dhcp server at the ISP part.
There is also a local nameserver in my network. Now I need to have the IP address of the local nameserver in the /etc/resolv.conf. Is there any way to put some default values through dhclient? Please advice me how to do it?
regards
libregeek.

nukkel · 11-18-2005, 01:12 AM

You can create a small "dhclient-enter-hooks" script to work with the dhclient-script. Read "man dhclient-script" for more info. Let us know if you can't work out how to do it -- I'll explain more in detail then.

Cheers,

libregeek · 11-18-2005, 02:24 AM

I have gone through the man pages of dhclient. But unfortunately couldn't get the idea. Can u please explain or give me some other resources on this?
regards
libregeek

nukkel · 11-18-2005, 04:43 AM

You have to create (as root) the file "/etc/dhclient-enter-hooks" with this in it:

Code:

#!/bin/sh
#
make_resolv_conf() {
    echo "nameserver 192.168.1.1" > /etc/resolv.conf
}

With 192.168.1.1 the actual address of your DNS server.
Next you must make this script executable: use the command "chmod 755 /etc/dhclient-enter-hooks"
Then restart dhclient and see if it worked!

What this thingy does is, it overrides the default make_resolv_conf() function (in /etc/dhclient-script)
with the new behaviour, i.e. just filling in /etc/resolv.conf with whatever we want, regardless of what the DHCP server says.

Let me know if it works for you!

pymehta · 11-18-2005, 05:18 AM

I was just going through dhclient.conf file for my dhcp config problem. Came across append and prepend statements. See if that is useful.

libregeek · 11-19-2005, 12:25 AM

nukkel:
I have worked out your suggestion. It worked but it replaced the nameservers that where inserted by the /etc/dhclient-enter-hooks. So now my /etc/resolv.conf has only the entry of my local nameserver. This is not what I expected. I have to append the local nameserver to the list of the namservers founfd by the dhclient.

However I also tried pymehta's suggestion. it worked for me. I have entered the following piece of code in the /etc/dhclient.conf.

Code:

append domain-name-servers     192.168.202.1;

This thing did all the stuff need for me. My heartiest thanks to both of you for your time spend on my issue and for the valuable suggestions.

regards
libregeek

nukkel · 11-19-2005, 11:41 AM

Glad to hear you solved it, I misread your first post, thought you _only_ wanted your local nameserver in /etc/resolv.conf... My bad :X