Re: Network topology

* Ian Mason · * Wed Oct 15 17:05:28 2008

On 15 Oct 2008, at 17:52, Colin Alston wrote:
On 2008/10/15 06:29 PM Bill Woodcock wrote:

InterMapper. http://dartware.com/network_monitoring_products/
intermapper/index.html

-Bill

Whoa, quite a serious looking piece of software. Will check it out.
Was kinda hoping to write my own software though, but perhaps I can
craftily learn something from it :)

If you have SNMP access pull:-
	1) Is it a bridge or a router?
	2) ARP Table
	3) MAC forwarding table
	4) Interfaces with MAC and IP addresses
	5) Netmasks
from each such router or bridge in the network. Use the information
from one to help you discover the

others recursively. Have a termination condition that stops this
process walking off your network and

attempting to discover the whole Internet.
That's enough to figure out both logical and physical topology.
Without SNMP (or similar) access it's nigh impossible to figure out.
If you only have access to a subset

of the routers and bridges in the network you MAY have enough to
figure out the topology - 50% is enough

if it's the right 50%.
Ian