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wiki:add_dns_server

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Add DNS Server

Jan 2017


Normally we just add the IP Address, Subnet Mask and Gateway to the ifcfg-eth0 file, as that is all we need. But if it is required that we need to update the OS, or add a piece of software (htop for example) then we may need to add the DNS settings.

While this was written with CentOs 6/7 in mind, it may work for other Linux distributions.

There are two ways this can be done.


Method 1


Use “PEERDNS=no”. This option will prevent /etc/resolv.conf from being modified by a DHCP server. So instead of using DHCP-provided DNS, you can specify any arbitrary DNS servers you want to use in /etc/resolv.conf.

The configuration file for your network interface (e.g., eth0) looks like the following.

sudo vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
PEERDNS=no


Then, add static DNS to /etc/resolv.conf

sudo vi /etc/resolv.conf

nameserver 8.8.8.8
nameserver 8.8.4.4



Method 2


Alternatively, you can specify DNS servers directly in the interface configuration file, instead of modifying /etc/resolv.conf yourself. That is:

sudo vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
DNS1=8.8.8.8
DNS2=8.8.4.4


The DNS servers specified with “DNS1/DNS2” directives will then automatically be added to /etc/resolv.conf when the interface is activated. So there is no need to modify /etc/resolv.conf yourself.

wiki/add_dns_server.txt · Last modified: 2017/02/28 18:00 (external edit)