Create sub interface or Secondary IP Address on Ubuntu/Debian

Create subinterface on Ubuntu – Debian without restart network service

1. Check present ip address on eth0

   root@ubuntu:~# ip addr
   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
   inet6 ::1/128 scope host
   valid_lft forever preferred_lft forever
   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
   link/ether 00:0c:29:17:b1:f4 brd ff:ff:ff:ff:ff:ff
   inet 192.168.0.106/24 brd 192.168.0.255 scope global eth0
   inet6 fe80::20c:29ff:fe17:b1f4/64 scope link
   valid_lft forever preferred_lft forever
   root@ubuntu:~#
   

2. Configure second IP address on subinterface

   root@ubuntu:~# ifconfig eth0:0 192.168.0.107 netmask 255.255.255.0
   root@ubuntu:~# ip addr
   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
   inet6 ::1/128 scope host
   valid_lft forever preferred_lft forever
   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
   link/ether 00:0c:29:17:b1:f4 brd ff:ff:ff:ff:ff:ff
   inet 192.168.0.106/24 brd 192.168.0.255 scope global eth0
   inet 192.168.0.107/24 brd 192.168.0.255 scope global secondary eth0:0
   inet6 fe80::20c:29ff:fe17:b1f4/64 scope link
   valid_lft forever preferred_lft forever
   root@ubuntu:~#
   

3. Create subinterface on Ubuntu – Debian permanently. Add eth0:0 interface to /etc/network/interfaces

   root@ubuntu:~# vi /etc/network/interfaces
   # interfaces(5) file used by ifup(8) and ifdown(8)
   auto lo
   iface lo inet loopback
   auto eth0
   iface eth0 inet static
   address 192.168.0.106
   netmask 255.255.255.0
   network 192.168.0.0
   broadcast 192.168.0.255
   gateway 192.168.0.1
   auto eth0:0
   iface eth0:0 inet static
   address 192.168.0.107
   netmask 255.255.255.0
   root@ubuntu:~#
   

4. Restart networking service

   root@ubuntu:~# /etc/init.d/networking restart
   Rather than invoking init scripts through /etc/init.d, use the service(8)
   utility, e.g. service networking restartSince the script you are attempting to invoke has been converted to an
   Upstart job, you may also use the stop(8) and then start(8) utilities,
   e.g. stop networking ; start networking. The restart(8) utility is also availabl e.
   networking stop/waiting
   networking start/running
   root@ubuntu:~# ip addr
   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
   inet6 ::1/128 scope host
   valid_lft forever preferred_lft forever
   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
   link/ether 00:0c:29:17:b1:f4 brd ff:ff:ff:ff:ff:ff
   inet 192.168.0.106/24 brd 192.168.0.255 scope global eth0
   inet 192.168.0.107/24 brd 192.168.0.255 scope global secondary eth0:0
   inet6 fe80::20c:29ff:fe17:b1f4/64 scope link
   valid_lft forever preferred_lft forever