Minimal CentOS 6.4 install, configuring DHCP for IPV4

When first installing CentOS 6.4 on most systems, you’ll need to configure DHCP to obtain an IPV4 IP address in order to connect to the network. This can be done by editing the network configs, you’ll need root access, so go ahead and switch users now:

[[email protected] ~]# sudo -su

Lets check to see if networking is enabled:

[[email protected] ~]# cat /etc/sysconfig/network |grep -i network

This should return NETWORKING=YES , if it does not, edit the file to make it say YES.

Lets get starting editing the config for eth0.

[[email protected] ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0

You’ll see something similar to this:

DEVICE="eth0"
HWADDR="08:00:27:07:9e:57"
NM_CONTROLLED="YES"
ONBOOT="NO"
[/bash]

There are two options we want to change here:

NM_CONTROLLED="NO"
ONBOOT="YES"

Now add this to the bottom:

BOOTPROTO="dhcp"

This will allow you to grab an IP from your DHCP and essentially enable IPV4.

The whole file should now look like this:

DEVICE="eth0"
HWADDR="08:00:27:07:9e:57"
NM_CONTROLLED="NO"
ONBOOT="YES"
BOOTPROTO="dhcp"

Save and close. Now, lets restart the network service to reload with these settings.

[[email protected] ~]# service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:
Determining IP information for eth0... done.
                                                           [  OK  ]

Notice the ‘eth0′ – awesome! Now lets check to see if we got an IPV4 from our DHCP!

[[email protected] ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:07:9E:57
          inet addr:192.168.0.110  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe07:9e57/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:24485 errors:0 dropped:0 overruns:0 frame:0
          TX packets:931 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2279234 (2.1 MiB)  TX bytes:114720 (112.0 KiB)
          Interrupt:19 Base address:0xd020

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

Sweet, we’re now up and running. That wasn’t so bad!