How is a chain of socks servers technically created?

Question

proxy

Explain technically how a chain is created through several socks servers? What is needed is a description at the protocol level, and not an example of a configuration in any finished product.
Preferably for Socks V5.

Answer 1

The proxy chain principle is the same for both SOCKS and HTTPS. I made a chain on HTTPS proxy like this:
1) I connect via TCP to proxy No. 1 (TCP connect to the desired address / port)
2) I ask the proxy to create a channel with proxy No. 2 (in my case, I send the packet "CONNECT 222.222.222.222" via TCP :8080")
3) The proxy connects via TCP to the specified address
4) I get a message from proxy #1 that the connection has been established ("HTTP/1.0 200 Connection established\r\n\r\n")
5) Next, proxy #1 simply redirects packets back and forth between me and proxy #2, without changing or processing them in any way. We forget about it, we consider that we have a direct TCP connection with proxy No. 2
6) Repeat steps 2-5 for all other proxies in the chain
7) We ask the last proxy to connect us to the desired site and again we are waiting for the message "Connection Established"
In the case of SOCKS proxy, commands and responses will be in SOCKS format, the rest is identical.