IP Aliasing

[Siraj Shaikh]

I have a query reagrding IP aliasing in FreeBSD. I have read up on it,
this has been helpful: http://freebsd.peon.net/tutorials/6/

I am wondering if anyone has some experience in using it, and what I
want to know

1) is there an upper limit to configuring a number of alias addresses?

2) if an interface is configured with an alias address, then what
address is shown on the traffic leaving this interface? So, for
example, if I were to ping this machine on its primary address, I
expect to get a response from the primary address of the interface.
What happens if I ping an alias address, would I get a response from
this alias address (as source IP on packets?), or would I get a
response from the primary address configured for the interface?

3) In the above scenario, all traffic leaving the interface
(regardless of the source IP on it) will have the same MAC address
(the one of the interface) - is that right?

4) Does anyone know if there are there any other network
characteristics or behaviour by which we can distinguish a machine
having more than one IP address (primary plus alias) configued on one
of its interface?

Thanks!

Siraj