What is the difference between SS, SSH, SSL, and VPN

At present, can reach the wall function of more than VPN, such as the more popular in recent years, the SS, but a lot of friends completely confused SS, SSH and SSL What is the difference between these connections or the protocol and VPN in the end which good? Here are some simple descriptions.

VPN here is not much to do introduction, is a virtual network, through a variety of connection agreements to establish a VPN network, mainly under the introduction of SS, SSH, SSL so that you can make a clear comparison of small partners.

SS that is shadowsocks, which is often said socks agent, an Android version of the Chinese name: Video Shuttle. Socks Agent: The socks agent differs from other types of proxies by simply passing packets without caring about the application protocol, which is an HTTP request, so that the SOCKS proxy server is much faster than the other types of proxy servers. Socks agent is divided into SOCKS4 and SOCKS5, the difference is that the SOCKS4 agent only supports the TCP protocol (that is, Transmission Control Protocol), while the SOCKS5 agent supports both the TCP protocol and the UDP protocol (that is, the user Packet Protocol), also supports various authentication mechanisms, Server-side domain name resolution, and so on. SOCK4 can be done SOCKS5 can be obtained, but SOCKS5 can do SOCK4 is not necessarily able to do.

SSH: Securityshell abbreviation, similar to http,ftp in the Internet hierarchy, belongs to the application layer protocol. The goal is to provide a secure transport and usage environment for the shell. Specifically, it is safe to remotely execute the command of a machine on another UNIX system, often using Telnet to achieve the same purpose without SSH, without safeguards.

SSL: Secure Sockets Layer (secure Sockets layer,ssl), a security protocol that Netscape (Netscape) introduced as a first edition of the Web browser, to provide security and data integrity for network traffic. SSL encrypts network Connections at the transport layer. This agreement and its successor are TLS. The two purposes are similar, are safe in the network environment to exchange data, the implementation of technology is similar. But because of their different status in the stack, they cannot be confused. Common HTTPS is typically a cryptographic technique that is assumed to be based on the SSL protocol.

Now you should basically understand how these abbreviations are different, in simple terms, VPN and SS are network connection types, and SSH, SSL are connection agreements, I hope to help. As for VPN and SS in the end which useful, before the article has introduced.