WalkerWiki - wiki.alanwalker.uk

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== Add DNS Server ======
<color orange>Jan 2017</color>

----


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.