NirSoft’s Wireless Network Watcher, for instance, is also a portable network monitor its 'continuous background scan' is arguably better than Wifi Guard’s 'every x minutes' approach and it has some useful settings, including for instance an option to execute the command of your choice when a new device is detected.

Only when some new device is uncovered, something which hasn’t been there before, will the program get excited and display an appropriate alert dialog as a warning. But once it’s done, when SoftPerfect Wifi Guard next rescans your network in 30 minutes, it will now display all your regular systems in reassuring green. Okay, it’s true, this setup process could take a while if the network is large. Then repeat the process until your network is fully documented. Please note, the program is free for Windows and Linux, but the Mac version costs $9.99.This is easily fixed, though: simply right-click a device you recognize, select Properties, check 'I know this computer or device' and maybe add something to the Comment box where you say what it is. It's also lightweight and entirely free (no adware concerns), so if you're interested then you can try the program without suffering any hassles, penalties or problems. SoftPerfect Wifi Guard does provide a simple extra layer of protection, though. Plainly this is no substitute for proper wireless network security, such as using the highest levels of encryption supported by all your network devices. SoftPerfect Wifi Guard will scan your system every half hour, though, and if anything new and unknown has connected in the meantime then you'll be informed via a suitable pop-up alert. Which, initially at the list, will probably dwindle to nothing at all.

If you recognise a device as legitimate - a network storage device, say, or another system on your network - then right-click it, select Properties, check 'I know this computer or device' and it'll be removed from the danger list. Anything that's clearly a part of the infrastructure, like the PC you're working on or your router will be flagged as green, but everything else will be marked as red: a potential intruder. The program requires no installation (the Windows build, anyway) - just run it, and SoftPerfect Wifi Guard will quickly scan your network and display any devices it finds.

SoftPerfect Wifi Guard is a simple tool which makes it easy to detect intruders on your local network.

Softperfect wifi guard