Linux – How to Make Name Server Address Permanent in /etc/resolv.conf

linuxnameserver

I can not retain name server address I set via /etc/resolv.conf. Every time I set the value, the network manager overrides it with default gateway on reboot.

How to set it right?

I would prefer a way other than changing name server in router.

Best Answer

It depends. Please read to the end.

If you do not have the package resolvconf installed, then it is easy: after changing it the way you like, issue the command

 sudo chattr +i /etc/resolv.conf

The command changes the file attributes, making it immutable (the +i option).

However, if you have the package resolvconf installed, the file /etc/resolv.conf may be transformed into a symbolic link, 

 # file /etc/resolv.conf
 /etc/resolv.conf: symbolic link to `../run/resolvconf/resolv.conf'

which is a file on a virtual file system, the epitomy of a non-permanent version. The funny thing is that you may not know you have resolvconf installed, because recent versions of Debian-like OSes come with it pre-installed. You can establish whether your distro has installed it for you by issuing the command:

 #whereis resolvconf
 resolvconf: /sbin/resolvconf /etc/resolvconf /lib/resolvconf /usr/share/man/man8/resolvconf.8.gz

Even most importantly, you can establish whether your /etc/resolv.conf has been transformed into a link by means of the command (file /etc/resolv.conf) above. If the reply is ASCII text, use chattr, otherwise...

If you use a static IP, the simplest thing is to add the following line (or some such thing)

 dns-nameservers 8.8.4.4 8.8.8.8

to the stanza defining the properties of your static interface in /etc/network/interfaces.

If you instead are on a laptop which connects all the time to different networks,you may follow LawrenceC's excellent suggestion. But, if you have resolvconf on your system, the correct (and simplest) way to provide for a fixed set of DNSs is to use the files in /etc/resolvconf/resolv.conf.d. In particular, the following files are used (see Stephane Graber's page):

base: Used when no other data can be found

head: Used for the header of resolv.conf, can be used to ensure a DNS server is always the first one in the list

tail: Any entry in tail is appended at the end of the resulting resolv.conf.

So place you favorite nameservers in head, as follows

  nameserver 8.8.8.8

and you are done.

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