Add second IP-address to interface in 17.10

Question

How do I add a second IP-address in Ubuntu 17.10 like the old days where you could add eth0:1, eth0:2 etc.

I've tried but lots of commands have been deprecated like ifup, ifdown etc. and the network settings doesn't seem to be the same as it used to. I might be wrong here but I can't seem to figure it out.

I have a network card eth0 where I want to add a second IP on the same subnet. If I add eth0:1 to /etc/network/interfaces but I can't seem to get the interface up.

Is there another way to do this permanently?

EDIT:

/etc/network/interfaces:

auto lo
iface lo inet loopback

auto eth0:1
iface eth0:1 inet static
    address 10.100.1.39
    netmask 255.255.255.0

I've tried to add the information on eth0 too but it doesn't seem to make a difference.

This if the output of ifconfig

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet 10.100.1.38  netmask 255.255.255.0  broadcast 10.100.1.255
    inet6 fe80::215:5dff:fe00:1605  prefixlen 64  scopeid 0x20<link>
    ether 00:15:5d:00:16:05  txqueuelen 1000  (Ethernet)
    RX packets 496  bytes 248506 (248.5 KB)
    RX errors 0  dropped 4  overruns 0  frame 0
    TX packets 241  bytes 34934 (34.9 KB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Answer 1

Turns out in 17.10 you edit your network settings in /etc/netplan/01-netcfg.yaml

All I had to do was add the second IP next to the existing one separated with a comma like this:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
     addresses: [ 10.100.1.38/24, 10.100.1.39/24 ]
     gateway4: 10.100.1.1

Then you run:

# netplan apply

Hope this helps someone in the future.

Answer 2

You can do that directly on the commandline, which is not permanent (i.e. reboot-save)

sudo ifconfig eth0:0 10.100.1.40 netmask 255.255.255.0 up

or in your /etc/network/interfaces, which is permanent

sudo nano /etc/network/interfaces

add this (or similar) to the existing eth0 block

iface eth0:0 inet static
  address 10.100.1.40
  netmask 255.255.255.0

and bring it up with

sudo ifup eth0:0