# Terminology

• Check-in — is an event when the server with the installed product pings CLN and sends the information about its availability and state.
• Default Activation Key — it is a general activation key displayed all over CLN interface for quick access to it.
• IP Range — it is a range of IP addresses that are allowed for a particular activation key. Servers with IPs that are not in the range will not be activated with this activation key.
• Server License — this is a product license that allows to activate it on the servers. For example, 3 server license means it is possible to active one copy of product on one server.
• Server Limits — a number of servers that can be registered with a particular key.
• License Type — a type of server license that is used in Imunify360 and determines a limit of  server users. Among other products, Imunify360 has different types of server licenses:
  • Single User — good for servers with only one user in the system;
  • Up to 30 users — good for servers with users quantity less than or equal to 30;
  • Up to 250 users — good for servers with users quantity less than or equal to 250;
  • Unlimited — good for servers with any quantity of users (more than 250).
• User —  a registered user on the installed server:
  • For cPanel, Plesk, and DirectAdmin hosting panels it calculates the number of users in it, excluding system users.
  • For more details on user count calculation see the following article.