ACME is a communications protocol for automating requesting, fetching and renewing SSL/TLS certificates from certificate authorities.

CGI defines how web servers interact with an external program in order to generate dynamic content. Such programs can be written in any programming language including C, Perl and PHP.

Each computer on a TCP/IP network has usually one or more host names. Networking software transparently translates them to IP Addresses for internal use.

HTML is a markup language used to describe web pages.

HTTP defines how browsers and web servers communicate over a TCP/IP network.

IP is a low level networking protocol. It defines how computers can exchange messages over a network. IP is usually used in conjunction with TCP, a higher-level protocol.

An IP Address is a unique identifier for a computer connected to a TCP/IP network. It is made of four numbers separated by dots. Each number is between 0 and 255.

XSSI are a set of directives that can be included in HTML pages and processed by the web server to create simple dynamic documents.

TCP is a high level networking protocol. It allows establishment of virtual connections between computers to send and receive data streams. TCP relies on IP.

TCP/IP is a protocol suite developed by the U.S. Department of Defense for communications between computers. It has become the de facto standard for data transmission over networks, including the Internet. TCP and IP are the main protocols of TCP/IP.

An URL is the address of a document or a resource available on the Internet.