Setup Static IP Address ONBOOT

Assuming you are using eth0
Note this will work for any version of CentOS and basically any version of Redhat Linux or Redhat based distribution.

You would need to create a new file

[code:1:02f8d34c30] /etc/sysconfig/network-scripts/ifcfg-eth0:0[/code:1:02f8d34c30]

DEVICE=eth0:0

the ":0" at the end specifies alias 0 we could actually change this to ":99" or ":blabla" and it will still work.

The rest should be straight forward as long as you know how to set a static IP in general.

Edit your new file:

[code:1:02f8d34c30]/etc/sysconfig/network-scripts/ifcfg-eth0:0[/code:1:02f8d34c30]

And it should look like this:

[code:1:02f8d34c30]DEVICE=eth0:0
BOOTPROTO=static
IPADDR=ip.ip.ip.ip
NETMASK=255.255.255.0
GATEWAY=ip.ip.ip.ip
ONBOOT=yes[/code:1:02f8d34c30]

One more thing, to apply the changes and make them active and test what happens after a reboot

type [code:1:14b16772c8]"service network restart"[/code:1:14b16772c8]

One more thing, it can be a great thing to have a combination of a "DHCP" dynamic IP address and setting a static one.

This sort of guarantees network connectivity, say eth0 doesn't get an IP lease from the DHCP server then your server is basically down.

But if your eth0:0 alias is set statically then you can connect through the static IP address.

It just makes good sense!