How To: Make Sure /etc/resolv.conf Never Get Updated By DHCP Client
Option # 3: Configure dhclient.conf
/etc/dhclient.conf or /etc/dhcp/dhclient.conf file contains configuration information for dhclient. You can turn on or off DNS update and other options for specific interface or all interface using this file. The man pages for DHCLIENT.CONF and DHCP-OPTIONS point out that in dhclient.conf, you should add this:
supersede domain-name-servers 202.54.1.2, 199.2.3.4;
OR
prepend domain-name-servers 1.2.3.4, 1.2.3.5;
Here is a sample config for you:
timeout 60;
retry 60;
reboot 10;
select-timeout 5;
initial-interval 2;
reject 192.33.137.209;
interface "eth0" {
send host-name "laptop-area51.nixcraft.net.in.home";
send dhcp-client-identifier 00:30:48:33:BC:32;
send dhcp-lease-time 3600;
supersede domain-search "net.in.home", "cyberciti.biz", "vpx.nixcraft.net.in";
prepend domain-name-servers 8.8.8.8, 127.0.0.1;
request subnet-mask, broadcast-address, time-offset, routers,
domain-search, domain-name, domain-name-servers, host-name;
require subnet-mask, domain-name-servers;
}
Parent: Internet and Networking
The default setup of Ubuntu does not make it easy to use static DNS servers while using DHCP. If you use the standard ubuntu way of networking (ifupdown), you can edit /etc/network/interfaces
In that file you find the entry for your interface. If your interface is eth0, then look for the following lines:
auto eth0 iface eth0 inet dhcp
Add one line, so it looks like:
auto eth0 iface eth0 inet dhcp dns-nameservers ip.address.of.nameserver
Run
sudo invoke-rc.d networking restart
To make the changes effective
If you do not use ifupdown, you need to edit /etc/dhcp3/dhclient.conf
Find the lines
#prepend domain-name-servers 127.0.0.1;
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, host-name,
netbios-name-servers, netbios-scope;
And change them to
prepend domain-name-servers 1.2.3.4, 1.2.3.5;
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, host-name,
netbios-name-servers, netbios-scope;
Replace 1.2.3.4 and 1.2.3.5 with the addresses of your DNS servers.
Run
sudo invoke-rc.d networking restart
To make the changes effective: