Ask HN: Software licensing,protection,and distribution

What are some good resources for understanding the how different models work? I'm particularly interested in the best way to delivery a running client/agent to customers that communicates to our cloud servers. I currently stamp our clients to only be able to communicate with certain URLS and have a pinned TLS cert.

It would seem like a good model for me would be to let everyone download the clients off our website and have them put in a license key at install.