Change DNS settings on Linux

  • Last updated on: 2016-04-12
  • Authored by: Jered Heeschen

There may be times you need to change your server’s DNS settings, either because you find they’re misconfigured or because you want to use your own. Fortunately, there isn’t a lot of work involved in changing the DNS servers, just a quick edit in the right place.

Add name servers to the config file

On Linux, the DNS servers the system uses for name resolution are defined in the file:


In that file, you should have at least one nameserver line (two is better, so you have a fallback). Each line defines a DNS server.

The name servers are prioritized in the order the system finds them in the file. Use the IP addresses of the name servers when entering them, since the system won’t know what to do with domain names until after it knows how to get to the DNS servers.

Open resolv.conf with an editor, such as nano, to make the necessary changes (if it doesn’t exist already, this command creates the file):

sudo nano /etc/resolv.conf

The following table displays which name server IP addresses to use depending on which datacenter houses your cloud servers:

Datacenter Name server IP
Hong Kong (HKG) nameserver
London (LON) nameserver
Chicago (ORD) nameserver
Dallas/Fort Worth (DFW) nameserver
Sydney (SYD) nameserver

After you have your DNS servers set, save the file.

The easiest way to make sure your new settings are working is to try to ping a domain name:

ping -c 3

You should see a result similar to the following:

PING ( 56(84) bytes of data.
64 bytes from icmp_req=1 ttl=249 time=25.3 ms
64 bytes from icmp_req=2 ttl=249 time=25.2 ms
64 bytes from icmp_req=3 ttl=249 time=25.2 ms

--- ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 25.236/25.292/25.392/0.147 ms

If you get an unknown host message back, you should double-check the IP addresses you set as your DNS servers.

Name servers with IPv6 addresses

If you’re using IPv6 on your server, you may need to add the IPv6 addresses of your name servers to resolv.conf. You can see if a DNS server has an IPv6 address with two steps.

  1. Use host to get the name of the server:

    $ host domain name pointer
  2. Use the domain name you got back in another host lookup:

    $ host has address has IPv6 address 2001:4800:d::1

If an IPv6 address is returned, you can add that as another nameserver line in resolv.conf, as in:

nameserver 2001:4800:d::1

Then test as previously shown, using the ping6 command instead of the regular ping command to force the system to use IPv6.

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