Add IP Range to Centos / RHEL

If you want to quickly fill a subnet with ip addresses for a host, instead of manually adding interface aliases to the rc.local you can achieve the same thing with core networking support by doing the following in RHEL / Centos

in /etc/sysconfig/network-scripts

add a file called

ifcfg-ethX-range0

here ethX is the network interface ID you want to have the alias range on, so for eth0 you could use

ifcfg-eth0-range0

Using your favorite text editor, vi, pico, gedit, in our case, vi add the following

IPADDR_START=
IPADDR_END=
CLONENUM_START=
NETMASK=

Now you will need to fill this out, so for example

IPADDR_START=192.168.1.10
IPADDR_END=192.168.1.100
CLONENUM_START=0
NETMASK=255.255.255.0

The “CLONENUM_START” value is equal to the alias interface number you would start with this range. In this case, the first IP  will be binded to “eth0:0″. While you can start with any value for simplicity its best you start with a single digit number

If you do not have CENTOS/ RHEL or are using something other than these , you can always edit the rc.local and add interface aliases manually

For Example

/sbin/ifconfig eth0:0 192.168.1.10 netmask 255.255.255.0

will work with most distrobutions, including RHEL, CENTOS. Slackware, SuSe, for Ubuntu you may need to make the line

sudo /sbin/ifconfig eth0:0 192.168.1.10 netmask 255.255.255.0

‘The easiest way to check is at the root rompt # type the command

which ifconfig

on most RPM distros this comes back as /sbin/ifconfig, if your path is different than above, then change the ifconfig path to suite your needs.