Introduction to the proxy protocol SOCKS5 (zz)

If your machine has a valid Internet IP address, or you use a modem on your machine to dial up the Internet, you can

With free communication with any hosts on the Internet, you do not have to worry about the SOCKS5 protocol.
For machines in the internal network, the SOCKS5 Protocol needs to be accessed through some machines in the network that can connect to the external Internet.

Useful for external use.

SOCKS5 is a proxy protocol. It plays an intermediary role between the front-end machine and the server machine that uses the TCP/IP protocol for communication.

Allows front-end machines in the Intranet to access servers in the Internet or make communications more secure.

The SOCKS5 server simulates a front-end behavior by forwarding requests sent from the front-end to the real target server. Here,

The frontend and SOCKS5 communicate through the TCP/IP protocol. The frontend sends the request originally sent to the Real Server to the SOCKS5 server.

Server, then the SOCKS5 server forwards the request to the Real Server. When the SOCKS5 server sends a Communication Request to the real server

In the process, the request packet itself is not changed. After receiving the response from the Real Server, the SOCKS5 server forwards the response to the front-end.

.

Therefore, the SOCKS5 protocol is a proxy protocol that can adapt to various TCP/IP-based application layer protocols and is almost omnipotent.

. Although it cannot understand the internal structure of the data forwarded by itself, it can faithfully forward the communication packet to complete the work that the Protocol would have done.

Yes.

Unlike the SOCKS5 protocol, HTTP proxy is implemented through HTTP. The HTTP Proxy Server software understands the internal structure of the communication package,

In the forwarding process, we also need to modify and convert the communication program. Different from the HTTP Proxy protocol, SOCKS5 is actually a Transport Layer

.

We can imagine that if each specific application layer protocol needs to design a corresponding proxy protocol expression method, a specific proxy service

In any case, the server does not support so many new protocols. Therefore, it can be said that the emergence of SOCKS5 relieves the need for special

Difficult to design proxy protocols.

However, not all applications that use TCP/IP protocols can communicate through the SOCKS5 server unconditionally.

The front-end software must have interfaces of SOCKS5 to use the SOCKS5 proxy server.

A front-end that supports the SOCKS5 protocol usually has two running states:

1) Direct communication status, without using the SOCKS5 interface. At this time, the communication is for the final server.

2) SOCKS5 status. Use the SOCKS5 interface to send requests to the final server to the SOCKS5 server. Before

When initiating a session with the SOCKS5 server, the front-end tells the SOCKS5 server about the IP address and end of the final Server

Port information, so the SOCKS5 server can faithfully start the communication process with the final server according to the requirements of the front-end.