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Date: Tue, 25 Jan 2005 14:05:44 -0800 (PST)
From: Rich Wales <richw@richw.org>
To: freebsd-stable@freebsd.org
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Subject: Re: NIC acting promiscuously -- how to fix?
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Doug Hardie wrote:

> To verify what your interface is accepting use:   tcpdump -pei rl0
> That will show the packets that it accepts including the ethernet
> headers.  Those headers should all have your MAC address in them
> (send or receive).

Very good suggestion.  Thanks.

After running the above command for a while, and examining the output,
it turns out that the large amount of traffic on my external net is
mostly ARP "who-has" requests (sent to the broadcast MAC address).
These are, of course, legitimate.

There is also a relatively small number of multicast packets -- most
of which are MDNS (multicast DNS).

So, I was mistaken; my NIC doesn't have a "promiscuity" problem after
all.  Sorry for raising a needless alarm.

Rich Wales            richw@richw.org            http://www.richw.org