How to find MAC addresses on network?

[Chris G]

On Thu, Jan 22, 2009 at 03:47:36PM -0700, Smoot Carl-Mitchell wrote:
> On Thu, 2009-01-22 at 21:54 +0000, Chris G wrote: 
> > Is there a (reasonably) straightforward way of finding the MAC
> > addresses of systems (well, strictly, interfaces) on a network?
> > 
> > arping works for some but not all of my hardware, presumably some
> > things (like my HP printer) don't respond to arping.  What can I use
> > to find the MAC address of the printer?
> 
> Gee, I hope your printer responds to ARP requests.  If it does not, it
> is broken.  A trick I have used is to ping the local network's IP
> broadcast address and then peek at the ARP cache.  After that I can see
> the MAC addresses of all the devices on the network. e.g.
> 
> sudo ping -b 192.168.128.255
> arp -a
> 
> Do not do this on a production network or a large network or you might
> get a call from the network admin. :-)

I'm the 'network admin'!  :-)

Yes, as several people have pointed out, arp is the way to go after
having kicked the various interfaces on the network.  It seems my HP
printer isn't very well behaved though and I'll have to resort to
other means for that (like looking at its insides or rear panel).

-- 
Chris Green