vlan without ip address

[saeedeh motlagh]

thank you guys for your answers but my problem is not solved yet:((

the thing is, i wanna have something like this:
a freebsd box which acts like switch (for example cisco 2960). i want to
define vlanX on one interface (without any ip address) and it tags any
passing packets through that interface as vlanX (any passing packet will
have vlanX ID).

i've tried bridging interfaces (to simulate vlan ports) but its problem is
that it doesn't perform any vlan tagging.
i've also tried defining vlan as sub-interface. but problem is, it doesn't
tag every passing packets on real interface (it only works if we set ip
address for vlan, and then it just tags packets which their destination is
ip address of vlan sub-interface)

does anyone knows what should i do?

Cheers.

to me, the most important thing is that i is to vlan tagging while
configure vlans without any ip addresses. is it possible?