NMAP

NMAP is a mighty tool capable of scanning your network for devices connected to your router.

Here some examples of its capabilities:

First, there’s -sP, we can see what is currently connected,

then we can use -sT <ip> to see which ports are open on a device,

with -p <port> <ip> we can see if a specific port is available on a device.

If we want to know the OS (Operative System) of a device, we can do -O <ip> to find that out,

and to use the 3 (three) above filters in a single one, we can use -sS -O -T3 -oA invent <network>.

That would be the 5 (five) most used commands (probably). There are a lot more like -sL that shows all IPs and which devices were connected to them,

there is also -traceroute that while similar to -sS -O -T3 -oA invent network>, in this instance, it gives more information like the number of hops and MAC address.

And with the last one -iflist, we can see our machine’s IPs and MACs.

Do bear in mind that all information disclosed in this post was simply intended for educational purposes and should not be used for illicit goals!