FTP
FTP servers are computers that provide storage space on the Internet. They provide services in accordance with the FTP protocol. The full name of FTP is File Transfer Protocol (File Transfer Protocol). As the name suggests, it is a protocol specifically used to transfer files. Simply put, a server that supports the FTP protocol is an FTP server. (http://baike.baidu.com/view/106754.htm)
SSH
SSH is the abbreviation of Secure Shell, formulated by the IETF Network Working Group; SSH is a security protocol based on the application layer and the transport layer. SSH is currently a more reliable protocol designed to provide security for remote login sessions and other network services. Using the SSH protocol can effectively prevent information leakage in the remote management process. SSH was originally a program on UNIX systems, and then quickly expanded to other operating platforms. SSH can compensate for loopholes in the network when used correctly. The SSH client is suitable for multiple platforms. Almost all UNIX platforms—including HP-UX, Linux, AIX, Solaris, Digital UNIX, I rix, and other platforms—can run SSH. (http://baike.baidu.com/view/16184.htm#sub5909252)
HTTP
HyperText Transfer Protocol (HTTP, HyperText Transfer Protocol) is the most widely used network protocol on the Internet. All WWW documents must comply with this standard. The original purpose of designing HTTP is to provide a way to publish and receive HTML pages. In 1960, American Ted Nelson conceived a method of processing text information through a computer, and called it hypertext, which became the foundation for the development of the HTTP hypertext transfer protocol standard framework. Ted Nelson organized and coordinated the World Wide Web Consortium (World Wide Web Consortium) and the Internet Engineering Task Force (Internet Engineering Task Force) to jointly research, and finally released a series of RFCs, among which the famous RFC 2616 defines HTTP 1.1.
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Telnet
The Telnet protocol is a member of the TCP/IP protocol suite, and is the standard protocol and main method of the Internet remote login service. It provides users with the ability to complete remote host work on the local computer. Use the telnet program on the end user's computer to connect to the server. Terminal users can enter commands in the telnet program, and these commands will run on the server as if they were entered directly on the server's console. The server can be controlled locally. To start a telnet session, you must enter a user name and password to log in to the server. Telnet is a commonly used method to remotely control a Web server. (http://baike.baidu.com/view/44255.htm)
HTTPS (full name: Hypertext Transfer Protocol over Secure Socket Layer) is an HTTP channel with security as the goal. Simply put, it is a secure version of HTTP. That is, the SSL layer is added under HTTP, and the security foundation of HTTPS is SSL, so SSL is required for the details of encryption. It is a URI scheme (abstract identifier system), the syntax is similar to the http: system. Used for secure HTTP data transmission. https: URL indicates that it uses HTTP, but HTTPS has a default port different from HTTP and an encryption/authentication layer (between HTTP and TCP). The initial research and development of this system was carried out by Netscape, which provided identity verification and encrypted communication methods. Now it is widely used in security-sensitive communications on the World Wide Web, such as transaction payments.