Does the latest version support reverse connections?

[worm001]

As the question goes, I have a service on port 3333 on the intranet. How should I set up the client to access it on a server with a public network?

[vi]

What do you mean by "a service"? How is it related to Websocat? Is it a WebSocket-based service?

Typically you should use a software like Nginx or Caddy for customer-facing web server which delegates (reverse proxies) requests to real backends, possibly on other internal hosts. This includes WebSocket-based backends - WebSockets are also supported by nginx/caddy.