On Tue, 14-Nov-2000 at 21:41:07 +0000, John P . Looney wrote:
> I'm trying to work out what hosts are on a network. I thought it would be
> just a matter of doing a broadcast ping, but it seems at least some
> machines don't respond to it (like Win98 machines, for a start) - which
> they are perfectly entitled to do.
Active approach: Walk through the entire subnet firing off ARP requests
and watching for responses. It's still a lot of work, but it's slightly
less network traffic than using ping (which would have to do the ARP
requests anyway, after all).
Passive approach: Sit there on the network, and watch all the ARP traffic.
After watching for a while, you'll have the IP address of any machine that
ever bothers to talk on the network. Of course, this could take a while
before you would be very sure of getting all the machines.
Writing code for either approach is left as an exercise for the reader ;-).
... To study a subject best, know it well before you start.
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