virtual interfaces & vlans
I have an Ubuntu Server 12.04 machine with one physical NIC connected to a trunk port on a Cisco switch. I've installed the vlan package and configured /etc/network/interfaces to use 5 virtual interfaces with static IPs with vlan tagging, each on a different vlan.
The problem I've run into is that only one of the virtual interfaces seems to be "active" at a time, meaning only one of the IP addresses can be pinged. Sometimes, with a restart, which interface this works on will change. I had read that I should only configure the gateway on one of the interfaces, so I did, but that's not even the interface that always works!