Setting up CentOS – Configure the network

When you install a CentOS 6.0, 6.1, or 6.2 server, the network is not automatically configured for DHCP or static IP addressing. In CentOS 6.3 and higher, the server is set for DHCP, but it is not set to automatically start on bootup. In CentOS 6.3, you must configure ONBOOT=yes in the /etc/sysconfig/network-scripts/ifcfg-eth0 file.

Static IP Address

In this example, our network has a 10.0.1.1 gateway, a DNS server at 10.0.1.2, another DNS server at 10.0.1.3, and we want to set the server to an address of 10.0.1.10. Modify values as appropriate for your setup.
Use vi or your editor of choice to make the following changes.
Edit /etc/sysconfig/network-scripts/ifcfg-eth0 and add the following parameters:

DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
IPADDR=10.0.1.10
NETMASK=255.255.255.0
BROADCAST=10.0.1.0
GATEWAY=10.0.1.1
DNS1=10.0.1.2
DNS2=10.0.1.3

Edit /etc/sysconfig/network and add the following to enable the network:

NETWORKING=yes

OPTIONAL: If you find that your server is not correctly resolving addresses on your domain, edit /etc/resolve.conf and added the following so that it searches your base domain.

search domain.com

DHCP IP Address

Modify values as appropriate for your setup.
Use vi or your editor of choice to make the following changes.
Edit /etc/sysconfig/network-scripts/ifcfg-eth0 and add the following parameters:

DEVICE=eth0
BOOTPROTO=DHCP
ONBOOT=yes

Edit /etc/sysconfig/network and add the following to enable the network:

NETWORKING=yes

OPTIONAL: If you find that your server is not correctly resolving addresses on your domain, edit /etc/resolve.conf and added the following so that it searches your base domain.

search domain.com

References: http://www.pwrusr.com/system-administration/solved-centos-6-networking-and-hyper-v