Adding additional IPs to Linux

Adding additional IPs to Linux

 

Using ifconfig

Adding 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

As example below

ifconfig eth0:0 192.168.10.2 netmask 255.255.255.0 up

Making sure 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]

As the  example

ip address add 192.168.63.43/24 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:

Linux

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 192.168.0.20

gateway 192.168.0.1

netmask 255.255.255.0

 

You can add as many blocks as you need. by changing eth0:1 for eth0:2, eth0:3 and so on.