I am fairly new to ArcGIS Server and am a bit confused about sharing settings. I have my server linked to my organizations ArcGIS Online portal (we are currently not using a federated server with our own portal). After doing so, I set the sharing on a particular service to a specific group I had previously created. However, after doing so, I was still able to access the service URL without being logged in. I wish to be able to restrict this type of access because we will have some services were share widely, others we won't. And once a user has one service URL, they can easily access other services.
I am rather certain I did something wrong, so any pointers in the correct direction would be greatly appreciated.