howto lock DNS number in /etc/resolv.conf

Tom Horsley horsley1953 at gmail.com
Sun Aug 21 01:00:32 UTC 2011


On Sat, 20 Aug 2011 20:36:55 -0400
james tate wrote:

> How can I lock down DNS nameserver in /etc/resolv.conf , every time I 
> reboot the DNS is changed ?

Two ways: Edit the /etc/sysconfig/network-scripts/ifcfg-<whatever>
script for the interface associated with the router providing the
bad info and add the line:

PEERDNS=no

You might have to reboot a couple of times after that to get the
network properly shutdown and restarted with the PEERDNS=no
line in place.

After the reboots, it should be safe to manually edit /etc/resolv.conf
and the contents should remain undisturbed from that point on.

If that doesn't fix it, there is always the big hammer:

Edit /etc/resolv.conf the way you want it, then do:

chattr +i /etc/resolv.conf

That sets the "immutable" attribute so even root can't modify
the file. (If you ever want to modify it again, you'll need
to do chattr -i first).

P.S. This only works for redhat based distros. The rules to
achieve the same PEERDNS=no effect on other distros vary wildly
(the most wacko being opensuse).


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