I have been given a company network to perform layer 2 and layer 3 network discovery.
I have to find out the network topology and infomation about network equipments including switch, router, server, firewall, etc.
I have some knowledge of SNMP and planning to use a tool such as WatsUpGold to do my task.
The company network consists of three sites Site A, Site B and Site C with network address 192.168.1.0/24, 192.168.2.0/24 and 192.168.3.0/24 respectively.
But here is the tricky part.
I do not know if all network devices support SNMP, and if they do, what Community string and login credentials I should use in order to discover network equipments and the topology.
I am not even sure if tools like WhatsUpGold could do my job.
To simply put my question, what and how should one perform network audit and discovery of blackbox network.