How to get Mac address of ethernet port?

[Roy Smith]

In article <mailman.5336.1389476410.18130.python-list at python.org>,
 Chris Angelico <rosuav at gmail.com> wrote:

> We had a connection set up a few years
> ago where the ISP tech recorded the source MAC into the far end, and
> only that MAC would work - so when I stuck in a different router, I
> needed to switch it to the old MAC before it could establish a
> connection. Stupid? Yes. Unusual? I hope so

Actually, I think it's pretty common.

I had exactly the same problem a few years ago.  My DSL router fried 
itself.  I got a new one and it was easier to make it fake out the old 
router's MAC than to get my carrier to update their head end 
configuration[1].

[1] Roy's law of dealing with service providers.  Anything you can do 
yourself is easier than interfacing with tech support.