Add IP using ifconfig command line

You can use ifconfig command to configure a network interface and alias. For example:

• eth0 NIC IP 192.168.1.5


• eth0:0 first NIC alias: 192.168.1.6

To setup eth0:0 alias type the following command as the root user:
# ifconfig eth0:0 192.168.1.6 up
Verify alias is up and running using following command:
# ifconfig -a

# ping 192.168.1.6
However, if you reboot the system you will lost all your alias. To make it permanent you need to add it network configuration file.

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Copy etc/sysconfig/network-scripts/ifcfg-eth0 file as /etc/sysconfig/network-scripts/ifcfg-eth0:0
# cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0:0

Open file /etc/sysconfig/network-scripts/ifcfg-eth0:0 using vi text editor:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0:0

Find entry that read as follows:

DEVICE=eth0

Replace with:

DEVICE=eth0:0

Find entry that read as follows:

IPADDR=xxx.xxx.xxx.xxx
Replace it with your actual IP address:

IPADDR=192.168.1.7
At the end your file should like as follows:

DEVICE=eth0:0
IPADDR=192.168.1.7
NETMASK=255.255.255.0
NETWORK=192.168.1.0
ONBOOT=yes
NAME=eth0:0
Open file /etc/sysconfig/network-scripts/ifcfg-eth0 and make sure file does not have a GATEWAY= entry:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0

Find the entry that read as follows:

GATEWAY=your-ip
Remove or comment it out by prefixing # (hash) :

# GATEWAY=192.168.1.254
Save the file. Add the GATEWAY= to your /etc/sysconfig/network:

# vi /etc/sysconfig/network
Append or modify GATEWAY entry:

GATEWAY=192.168.1.254
Save the file. Reboot the system or run the following command:

# ifup eth0:0
OR

# service network restart
Red Hat / CentOS / Fedora Multiple IP address range

You can assign multiple ip address range as follows to eth0:
vi /etc/sysconfig/network-scripts/ifcfg-eth0-range0

Append following code from 202.54.112.120 to 202.54.112.140:

IPADDR_START=202.54.112.120
IPADDR_END=202.54.112.140
CLONENUM_START=0
NETMASK=255.255.255.0
Save and close the file.