one physical interface -> n virtual interfaces

[Mariano Cediel]

How do I create, from a physical interface, n virtual interfaces, but
all effects are real, their MAC different, on which we can do
individually NAT, etc, etc.?

I need one external interface has 2 public IPs, and I'll do every NAT
over every <interface> (with ipfw and divert)
individually (each of them has its own gateway)

A little help to start researching .....
Greetings.

(sorry for my poor english)

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