Friday, 31 August 2012

Centos 6/RHEL set up Static IP with Network Bridge

Setting up a Network Bridge on Centos 6/RHEL with a Static IP is relatively straightforward

The bridge enables virtual machines to be accessed from other hosts as if they are physical systems in the network.

$ sudo yum -y install bridge-utils

Rename your existing file and get some information from it

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

$ 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

Add the lines below to complete the file

# vi ifcfg-eth0                       

DEVICE="eth0"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
NM_CONTROLLED="no"
ONBOOT="yes"
TYPE="Ethernet"
BRIDGE="br0"

(Drop the UUID to the next line)

Save the file

Install iproute2 tools  

$ sudo yum -y install iproute          
$ route -n                             

$ netstat -nr  

The above commands fetch needed information                         
Create a bridge file                                   

# vi ifcfg-br0                         add the following

DEVICE="br0"
BOOTPROTO="static"
IPADDR=192.168.0.100
NETMASK=255.255.255.0
NETWORK=192.168.0.0
GATEWAY=192.168.0.1
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
NM_CONTROLLED="no"
ONBOOT="yes"
PEERDNS="yes"
TYPE="Bridge"

Replace the 4 network values with your own, you can get all the information from the 2 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

$brctl show                         

Shows the bridge details                   

$ ifconfig -a                        

Shows the new setup


br0       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:154 errors:0 dropped:0 overruns:0 frame:0
          TX packets:212 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:32630 (31.8 KiB)  TX bytes:88381 (86.3 KiB)

eth0      Link encap:Ethernet  HWaddr 00:02:44:4B:52:D8
          inet6 addr: fe80::202:44ff:fe4b:52d8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1048 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1129 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:383206 (374.2 KiB)  TX bytes:240253 (234.6KiB)
          Interrupt:18 Base address:0x8000


Some setups may require a reboot



See also a simple Static IP without a bridge.












1 comment:

  1. Thanks for your important concept information.

    ReplyDelete