Obtaining Ethernet addresses?

[lars at larsshack.org (Lars Kellogg-Stedman)]

> I will stop cluttering the list's queue with my pursuit after this
> message, but I don't believe the response addresses my quest -
> 
> It will give me the MAC address of the Ethernet card in the system, but I
> don't see how it gives me the MAC address of the cable modem connected to
> the PC's Ethernet card.    

If your cable modem is your default router, then looking at your ARP cache
will give you its MAC address.  This is what ARP does -- it associates IP
addresses with link-level addresses.

For instance, the output of 'arp -a' on my system includes the following:

  ? (146.115.xxx.xxx) at 02:00:0A:11:02:57 [ether] on eth2

This is my RCN cable modem [ mostly unused since I recently signed up for
AT&T's service, which has proven to be far more reliable ].  The second
address (02:00...) is the MAC address.

As your default router, the cable modem will have to be in your arp cache
because it's used every time a packet leaves your system destined for the
wide wide world.

Even if you don't have /proc/net/arp, you probably have an arp command
that will give you the same information.

-- Lars

-- 
Lars Kellogg-Stedman <lars at larsshack.org> --> http://www.larsshack.org/

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