This is a simple little Perl script usable as a filter, it picks up
MAC addresses and looks them up in CSV files in the format provided
by IEEE, adding the vendor name in brackets when printed.

$ arp -an | grep 192.168.41 | maclookup
? (192.168.41.23) at 78:2b:cb:1a:51:94 (Dell Inc.) on vlan410
? (192.168.41.25) at 00:30:48:53:62:8a (Super Micro Computer, Inc.) on vlan410
? (192.168.41.26) at 00:30:48:59:62:8a (Super Micro Computer, Inc.) on vlan410
? (192.168.41.34) at d0:67:e5:e8:c2:14 (Dell Inc.) on vlan410
? (192.168.41.35) at d0:67:e5:e8:c1:89 (Dell Inc.) on vlan410
? (192.168.41.36) at bc:30:5b:e7:ac:49 (Dell Inc.) on vlan410
? (192.168.41.68) at 00:11:43:17:85:bf (Dell Inc.) on vlan410
? (192.168.41.70) at 00:30:48:59:17:ad (Super Micro Computer, Inc.) on vlan410
? (192.168.41.81) at fe:e1:ba:d0:6b:47 (OpenBSD randomly generated: locally administered) on vlan410
? (192.168.41.82) at 76:e7:50:ee:f8:77 (Unknown: locally administered) on vlan410

As of version 1.3, command-line lookups are also available:

$ maclookup 00:04:20:07:b4:63
00:04:20:07:b4:63 (Slim Devices, Inc.)

And, for command-line only, partial lookups are supported:

$ maclookup b8:69:f4
b8:69:f4 (Routerboard.com)

The following formats of MAC address are recognized:

00:11:22:33:44:55  (standard notation)
001122-334455      (often found on HP switches)
