Friday, 31 August 2012

Centos 6/RHEL set up a Static IP

To set up a single Static IP on Centos 6/RHEL do the following

(This assumes you have an existing connection 'eth0')

Install iproute2 tools  

$ sudo yum -y install iproute  

First rename your existing file and get some information from it

$ sudo su

# cd /etc/sysconfig/network-scripts/

# mv ifcfg-eth0 ifcfg-eth0.bak

# cat ifcfg-eth0.bak   

Echo the HWADDR and UUID into your new ifcfg-eth0 file

# echo HWADDR="00:02:44:4B:52:D8" UUID="2609446d-e228-4600-ae9c-8230c1c3d7d3" > ifcfg-eth0

You can use the below commands to view the routing table.


$ route -n                            

$ netstat -nr                           

Add the lines below to complete the file


(Drop the UUID to the next line)

# vi ifcfg-eth0                       

DEVICE="eth0"
BOOTPROTO="static"
IPADDR=192.168.0.100
NETMASK=255.255.255.0
NETWORK=192.168.0.0
GATEWAY=192.168.0.1
NM_CONTROLLED="no"
ONBOOT="yes"
TYPE="Ethernet"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"


Save the file


Replace the four network values with your own, you can get all the information from the two commands above, this assumes you will know the static ip address range of your own router for the IPADDR.

(NETWORK will be under 'Destination', GATEWAY will be under 'Gateway' and NETMASK will be under 'Genmask'  using either route -n or netstat -nr commands)

# service network restart

To relaunch the new configuration

$ ifconfig -a                       

eth0      Link encap:Ethernet  HWaddr 00:02:44:4B:52:D8  
          inet addr:192.168.0.100  Bcast:192.168.0.255  
          Mask:255.255.255.0
          inet6 addr: fe80::202:44ff:fe4b:52d8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6071 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6899 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3804377 (3.6 MiB)  TX bytes:1416715 (1.3 MiB)
          Interrupt:18 Base address:0x8000 

Some setups may require a reboot


See also a Static IP with a Network Bridge.





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