promiscuous mode, was Re: [HECnet] Multinet Tunnel Connections to SG1::

[Dave McGuire]

On 06/08/2012 02:00 AM, Johnny Billquist wrote:
But reading it through now, I see that there was one implicit assumption
in my text which I could have pointed out.
If you need to share the device with the system, while using a different
MAC address, you need to place the device in promiscuous mode. And such
is the case if we talk DECnet, since DECnet requires that you use a
specific MAC address which is not the same as the default MAC address of
a device.

  In the case of Linux DECnet, it actually changes the "main" MAC
address of the interface, it doesn't add another one.

And to make a correction to your text, when not in promiscuous mode,
your ethernet controller will filter out packets that do not have your
MAC address, and packets that don't have the multicast bit set (possibly
you can also get it to filter more specific on multicast ethernet
packets, but multicast is a separate story from unicast packets on
ethernet controllers anyway).

  Oh yes, I'm sorry for my omission.

                    -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA