Are incoming connections to proxies possible?

Question

proxy

Hello. Sorry for the possibly noob question, but all the questions in the search engines regarding the proxy are clogged with SEO text.

Is it possible to accept incoming connections using proxies at all, or do they only work with outgoing ones?

Answer 1

SOCKS5 standard supports BIND function
https://datatracker.ietf.org/doc/html/rfc1928

BIND
The BIND request is used in protocols which require the client to
accept connections from the server . FTP is a well-known example,
which uses the primary client-to-server connection for commands and
status reports, but may use a server-to-client connection for
transferring data on demand (eg LS, GET, PUT).

Answer 2

Of course it is possible - but how do you think clients connect to them? :)

Answer 3

The proxy server cannot accept incoming requests and redirect to somewhere else, except for the actual use of the proxy.
Those. when a browser connects to a proxy can this be considered an incoming connection?
ps http proxy exception, from the point of view of the http proxy standard, this is a web server, requests to which must be formed in a special way, respectively, it will return the page as a regular web server