Linux add a second IP address, permanent or temporary

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Date: 2013-05-24 17:11:11 00:00

Add a secondary IP to Linux

Add a second temporary IP address

Using ifconfig

If you want to add a secondary IP address to a NIC already in use in Linux, and have that change only temporary. Enter this command:

ifconfig [nic]:0 [IP-Address] netmask [mask] up

An example is shown below

ifconfig eth0:0 192.168.1.2 netmask 255.255.255.0 up

You need to be root in order to execute that command.

Using ip command

If you prefer to use the ip command instead of ifconfig

ip address add [ip]/[mask-digits] dev [nic]

Here is an example

ip address add 192.168.99.37/24 dev eth0

With this command you can add more ip address to the same dev NIC, the second is considered as secondary.

Add a permanent IP address

Ubuntu

For Ubuntu systems, edit the /etc/network/interfaces file

vim /etc/network/interfaces

Add this for one extra IP

auto [NIC]:[n]
iface [NIC]:[n] inet static
address [ip.add.rr.ss]
gateway [gw.ip.ad.rs]
netmask [ne.tm.as.kk]

Here an example:

auto eth0:1
iface eth0:1 inet static
address 192.168.0.1
gateway 192.168.0.254
netmask 255.255.255.0

You can add as many blocks as you want. Just change eth0:1 for eth0:2, eth0:3 and so on.

If you are adding additional IPs to eth1, or eth2 also modify that on the example.