You’ve been hired at Connect Spree, a small but growing Internet service provider. One of your goals is to learn about network- that is, to determine it’s physical and logical topologies, access method, throughout rates, type of equipment, and the way this equipment is interconnected. Although you don’t yet have an access card that will let you into the secure telco rooms an equipment rooms, you have permission to log on to the routers and switches. What kind of network information can you see glean from issuing commands on a router or switch? What kind of information could you obtain from using commands on your workstation that’s connected to this network? What kind of information do you suppose would not be evident unless you could physically access the network hardware?

Sample Solution

It depends on the model of router and switch, but you can get quite a lot of data from e.g. BayStack such as routing tables, packet counts, ARP tables, filter entries, port characteristics, hardware status, firmware etc. So you can identify MAC addresses and ip address of equipment connected to the different ports, for instance
From a workstation you could run e.g nmap which will tell you about devices live on the network, including often fingerprinting information (operating system and version), running servers (open ports) and firewall state.
You can also interrogate many devices like printers using SNMP.

Without physical access, you will not be able to tell the colour of the wire insulation or how long the cables are. You won’t be able to tell how high off the floor a router is or which way it’s facing.