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Date: Mon, 28 Jan 2008 16:46:19 +0100 (CET)
From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Siraj Shaikh <siraj.shaikh@gmail.com>
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Cc: freebsd-questions@freebsd.org
Subject: Re: IP Aliasing
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>
> 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?

no idea, i have 37 without problems.

>
> 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
yes you will get from the IP you pinged.

> 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?

yes.

>
> 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?

it depends how services are configured.