I'm not sure about the syntax here: what comes first in
/etc/network/interfaces interface names, VLAN or alias? What I want is to setup two different subnets on the same VLAN (temporarily).
It will look something like below, where there's a 10.20.100.100/24 and 10.20.200.200/24 on the same VLAN (id 33):
iface eth0:1.33 inet static address 10.20.100.100 netmask 255.255.255.0 iface eth0:2.33 inet static address 10.20.200.200 netmask 255.255.255.0
I expected the Debian Wiki to answer this but it did not: https://wiki.debian.org/NetworkConfiguration#Multiple_IP_addresses_on_One_Interface