I wanted to do some occasional posts on some tools I use for various technical tasks. Partially just to suggest some useful stuff, partially so I have some posts to reference anytime I reference said stuff.
I wanted to start off with Netscan and Fing, which serve the same basic purpose on two different platforms. Both of these tools will scan the local IP range and return a list of every device connected to the network. Netscan is what I use on windows, Fing is what I use on Android.
I use these tools very frequently, several times a week on average. So what use is scanning the local network anyway? I have two main uses, though both come down to Device Discovery.
Firstly, basic device discovery. I’ve hooked something new to the network and I need to access it. A lot of what I connect is headless with no easy way of discovering the IP aside from a scan. An Arduino, a Raspberry Pi, a networked Webcam, all of these things need to be found once connected. The scan is also useful for getting the MAC address of devices on the network. The IP is dynamic on a network by network basis, a MAC address is a unique identifier. Knowing the MAC address is useful for building firewall rules and setting up static IPs assigned by the router for devices like phones or laptops where assigning IPs on the device can get hairy.
The other reason for doing a network based scan is intrusion detection. Generally speaking, I don’t expect to see hackers or anything on my home network. This is more for checking things like “if my kids’ devices are connected” or occasionally if one of my kids has a new device borrowed or whatever that I am not aware of on the network.
Ultimately I want to set up a little network monitoring system on a server to do these sorts of checks in real time but both of these tools have served me well for years as doing the job quickly and simply.
Both are also useful for poking around foreign networks. You can see what machines are on an open WiFi hotspot and see if they have any open shared files. Though some open hotspots are smart enough to block such scans.