====== Redhat - Networking - Set IP ======

===== Set Temporarily IP =====

1.  Set IP and netmask.

<code bash>
ifconfig eth0 10.20.1.10 netmask 255.255.255.0 up
</code>

where:

  * **eth0** is the name of the interface.
  * **255.255.255.0** is the netmask.
  * **up** is to activate the interface


2.  Set default gateway.

<code bash>
route add default gw 10.20.1.1
</code>

where:

  * **10.20.1.1** is your gateway ip.


3. Check the configuration.

Check the gateway:

<code bash>
route -n
</code> 

Check the ip address:

<code bash>
ifconfig 
</code>


===== Set Permanent IP =====

1.  Go to folder /etc/sysconfig/network-scripts

<code bash>
cd /etc/sysconfig/network-scripts
</code>


2.  Backup your existing configuration.

<code bash>
cp ifcfg-eth0 ifcfg-eth0.bak
</code>


3. Edit ifcfg-eth0 with your favorite editor

<code bash>
vi ifcfg-eth0
</code>


4. Add below line to the ifcfg-eth0 file to setup your ip

<file bash ifcfg-eth0>
BOOTPROTO=static
DEVICE=eth0
IPADDR=10.20.1.20
NETMASK=255.255.255.0
NETWORK=10.20.1.0
ONBOOT=yes
TYPE=Ethernet
</file>


5.  Save the file.


6.  Add below line to /etc/sysconfig/network to set your gateway.

<code>
GATEWAY=10.20.1.1
</code>


7.  Save and restart network

<code bash>
/etc/init.d/network restart
</code>


8.  Check your newly created ip.

Check the gateway:

<code bash>
route -n
</code> 

Check the ip address:

<code bash>
ifconfig 
</code>