I’ve also seen this but the price is frightening:
https://uk.rs-online.com/web/p/network-testers/0369564/
Or just something like:
https://www.ebay.co.uk/itm/Dahua-Dahua-PFM900-/324528668923?_trksid=p2349624.m46890.l49286
https://www.dynamic-cctv.com/iptester-pro.html