solaris virtual network interface nic ip network

Sometimes it’s useful to create a virtual network interface on your Solaris box, so that you can associate multiple IP addresses with the same host and not have to go through all the trouble of buying another NIC.

Here’s a quick HOWTO. Let’s assume our network card is eri0, and we want to create a virtual interface called eri0:1

Create the virtual interface:
# ifconfig eri0:1 plumb

Configure the virtual interface:
# ifconfig eri0:1 179.164.83.161 netmask 255.255.255.0 broadcast 179.164.83.255

Check to make sure it worked:

# ifconfig -a

lo0: flags=1000849 mtu 8232 index 1
inet 127.0.0.1 netmask ff000000
eri0: flags=1000843 mtu 1500 index 2
inet 179.164.83.160 netmask ffffff00 broadcast 179.164.83.255
ether 0:3:ba:9:63:9b
eri0:1: flags=1000842 mtu 1500 index 2
inet 179.164.83.161 netmask ffffff00 broadcast 179.164.83.255

Finally bring up your new virtual interface:
# ifconfig eri0:1 up

To make it come up on start:

create /etc/hostname.eri0:1 with hostname in it
make sure the hostname is in /etc/hosts

NOTE: The IP addresses in this story have been changed to protect the innocent.