You're likely thinking of PRTG from Paessler but to be fair there are a lot of options lol
https://www.paessler.com/prtg
Wifi sie of things
https://www.paessler.com/wifi-monitoring
I've used prtg in the past (don't really have much need these days) and it does have a free option, although really well hidden on the site. Basically the trial turns into the free option after so many days, has some restrictions obviously, but might do what you're after.any recommendations?
Thanks orcvader