By: bobkberg

bobkberg — Tue, 20 Dec 2005 19:12:15 +0000

This might take a little work, but since a hub repeats all traffic, and a switch doesn’t (Bear in mind that many switches these days aren’t manageable either), you might try something like this:

1) Ping everything in your subnet
2) Dump the ARP cache, and save it
3) Make note of your own MAC address
4) Run TCPDump/WinDump to capture level 2 packet headers using the -e (to print link-level addresses), and -s 16 to only capture the first 16 bytes, and save this data. Let it run for a while – like a day or whatever
5) Filter out any lines which contain your own MAC address, or broadcast addresses (FFFFFFFFFFFF).
6) Look for the default gateway’s MAC address. The number of different MAC addresses which are paired with the default gateway’s MAC address is likely close to the number of hosts on your local collision-domain (hub).

Bob

By: atomas

atomas — Tue, 20 Dec 2005 08:52:47 +0000

Hi.

A HUB is a HUB and is one of the most basic networked devices. It has it’s limitations and before installing servers on a HUB you should be aware of those limitations. Why don’t you just put your servers on a switch?

NOTE: HUB do not “have” MAC addresses, hosts&servers do.

Daniel Jutras
CISSP, CISA, CCSA, CCNA

Comments on: Discover a non IP element (ex: HUB)

By: bobkberg

By: atomas