[cknight]

Install NoRoot Firewall as HenryBemis mentioned, it's on the Play store. The app tells you what IP addresses apps are trying to communicate with in a fairly neat and simple way.

I've just installed it on my 6.1 Plus. Nothing sus yet but it's only been 5 minutes.

[LoneWolf]

I did install it too on my 6.1 and found the System app trying to connect to several cloudfront IPs, cant find any kind of extra info, did you find the same?