[Qemu-discuss] Networking and vlan

[Valerio Pachera]

Hi all, I'm trying to figure out how to manage networking in qemu.

I already use qemu-kvm 0.12.5 on debian squeeze.
I have a bridge on eth0 that "connects" the taps of the guests.
-net nic,macaddr=xx.xx.xx.xx.xx.xx -net tap
Now I need something to isolate the guests net from each other.
So I tried to run a guest with
-net nic,macaddr=xx.xx.xx.xx.xx.xx,vlan=2 -net tap,vlan=2
But I can still ping the other guests (and the host).

I know the sintax I used is obsolete. I read this:
http://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDYQFjAB&url=http%3A%2F%2Fwiki.qemu.org%2FDocumentation%2FNetworking&ei=eHSNT9H2Au_44QTZ7ZG1Dw&usg=AFQjCNEDsUHr6iu7osfwPKn_YRFpq2MoMw

May you explain me by simple words how vlan work and what are they usefull for?