How to Set Up DNS Lookup in Linux

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Q. How do I setup DNS Lookup under any Linux distribution ?

A. When an application (such as mail client or browser) makes a request which requires a DNS lookup, such programs send a resolution request to the local DNS resolver in the local operating system, which in turn handles the communications required. Under Linux resolver is configured via /etc/resolv.conf file. Open this file as a root user, enter:
# vi /etc/resolv.conf
Append or modify as follows into the file:
search nixcraft.com
nameserver 4.2.1.1
nameserver 4.2.1.2
nameserver 4.2.1.3
Save and close the file. Replace nixcraft.com with your actual domain name. 4.2.1.1 is first name server address. Save and close the file. Test setup, enter:
$ host cyberciti.com
$ host -t ns cyberciti.com
Sample output:

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cyberciti.com name server ns2.nixcraft.net.
cyberciti.com name server ns1.nixcraft.net.
cyberciti.com name server ns3.nixcraft.net.

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Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

3 comment

  1. A better setup is

    nameserver 4.2.1.1
    nameserver 4.2.1.2
    nameserver 4.2.1.3
    option rotate
    option timeout:1

    ‘rotate’ sets RES_ROTATE in _res.options, which causes round robin selection of nameservers from among those listed.
    ‘timeout’ sets the amount of time the resolver will wait for a response from a remote name server before retrying the query via a different name server.

  3. A better setup is

    nameserver 4.2.2.1
    nameserver 4.2.2.2
    nameserver 4.2.2.3
    option rotate
    option timeout:1

    (With a good dns server lol !)

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