sozotech
As other members have mentioned, you’ll need to install the software on the server you want to protect. If you go with per-website billing, you can cover multiple servers under a single license. This works well if you have a lower number of sites; for example, 100 sites across all your servers would only cost $10 per month. With per-website billing, you will be able to install cPFence on all your servers, no matter how many there are.
Both cPFence and cPGuard offer fully functional free trials, so the best approach is to try both and see which fits your needs better.
FWIW, a fully functional local UI is coming to cPFence within the next few days. This is not based on Enhance’s API, it’s built directly into cPFence and runs entirely on your server, making it fully GDPR-compliant. The new UI will include all security and cPFence WordPress bulk tools, allowing you to run them, edit configuration files, and adjust settings through a lightweight, easy-to-use interface. No more relying on the CLI or cheat sheets.