Mac – Discover the public ip of a network without being connected

ipmac addresstcpdump

Let say, I'm next to a network and can see the traffic (with airodump or similar tool) but can not decipher it (because I am not connected on the network). Is it possible to discover the public ip address of the network ?

I know the MAC address of the users connected on the network but do I know the one of the router ? If yes, maybe there is a way to do the matching. I know IP addresses are not forever but some addresses are static and never change. Maybe there is a database of MAC address having recorded that. Google has a database that match MAC address and geographical coordinates so why not with IP addresses ?

Other idea, if I know where am I, I can maybe guess the IP range used in the city by the ISP (is it findable ?) and then try to "ping" each IP on the range (if it is a /24, it's possible, even /16 maybe). Will I get some information like the MAC of the box or see some traffic on the network ?

These are two ideas I had. I don't know if they are doable, certainly not perfect. Do you think of some others ? By trying several methods, maybe I can get a guess with a bit of luck.

Thank you

Best Answer

If you are within the range of this network, why not just connect to it? Ask the network owner to provide you with the credentials and network settings you need and you're good to go. Working your way around a network security will only cause you headache, not to mention that it's illegal.