Is SOCKS5 bind persistent, or one-time only?

I've been studying RFC 1928 and the description of the BIND operation wasn't clear to me. The setup sequence is described as follows, as I underst开发者_开发技巧and it:

1. The client establishes connection to the SOCKS5 server
2. The client performs the CONNECT request
3. The client establishes new TCP connection to the SOCKS5 server and requests BIND
4. The server replies immediately with the result of the BIND operation
5. Upon receiving incoming connection, the SOCKS5 server sends the notification to the client

What is not immediately clear for me is the step 5. Do I have to re-request BIND afterwards to allow for more incoming connections?

As far as I understand, the same TCP connection (established at the step 3) is used for communication with the accepted peer. What if I need to keep accepting connections on the same address:port? Is it possible, after all?

You need a separate BIND request for each connection you want to accept, as there is only 1 notification sent back by the SOCKS proxy when a client connects to the bound port. Whether or not the SOCKS5 proxy allows multiple BIND requests on the same IP/Port depends on the proxy's implementation.