Hi @james.carson,
The individual (named user) subscription licenses (known as Desktop Subscription) require connection to the internet at first launch and then once again on a periodic basis - currently every 30 days. There are workarounds for certain environments that are mentioned in this prior post.
The shared (multi user) subscription licences (known as "network subscription) do not require a connection to the internet. Read more here if interested.
And of course, perpetual licenses, individual (SLM) or networked (NLM) do not require such a connection.
Do let me know if you want to discuss in more detail with a technical resources.
Hope this helps.
Regards, Felice
Felice S
Consumption Business Models Team