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

[Dave McGuire]

On 06/07/2012 08:16 AM, Johnny Billquist wrote:
Any program that needs access to raw ethernet packets needs to run as
root. Promiscuous mode or not. Promiscuous mode itself has little to do
with this.
So if you want to run anything like a bridge or a router, you will need
to run it as root. Promiscuous mode is basically just allowing you to
share the same interface as the system is otherwise using, instead of
having to dedicate a separate ethernet interface for this.

  Maybe you're just putting this another way, but promiscuous mode is
correctly defined a bit differently than this.   When an Ethernet
controller is placed into promiscuous mode, its on-chip MAC address
filters, which normally either select or ignore inbound packets based on
their MAC address, are disabled.   ALL packets are received by the
hardware and passed to the Ethernet driver in the OS, rather than only
the ones destined for that specific interface as defined by its MAC address.

  I'm reasonably certain that you know this but were just explaining it
in a more abstract way...?

                          -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA