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Date: Mon, 04 Nov 2013 06:25:59 -0800
From: Peter Grehan <grehan@freebsd.org>
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To: Aryeh Friedman <aryeh.friedman@gmail.com>
Subject: Re: how is the MAC for tap(4) computed?
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Hi Aryeh,

> There seems to be a very high rate of MAC address collisions when tap is
> running on different machines.... is there anyway to make the selection of
> MAC more random

  Do you mean, tap(4) when used with bhyve ? If so, bhyve calculates the 
MAC address for adapters based on an md5 hash of the PCI slot/function 
and VM name. If you use the same bhyve configuration on a different 
machine, the MAC address will be the same.

  If that's the problem, you may want to supply your own MAC address 
with the "mac=" parameter on the command line e.g.

later,

Peter.