pssl:port:ip
Listen on the given SSL port for a connection. By default, connections are not bound to a particular local IP address and it listens only on IPv4 (but not IPv6) addresses, but specifying ip limits connections to those from the given ip, either IPv4 or IPv6 address. If ip is an IPv6 address, then wrap ip with square brackets, e.g.: pssl:6640:[::1]. The --private-key, --certificate, and --ca-cert options are mandatory when this form is used.
ptcp:port:ip
Listen on the given TCP port for a connection. By default, connections are not bound to a particular local IP address and it listens only on IPv4 (but not IPv6) addresses, but ip may be specified to listen only for connections to the given ip, either IPv4 or IPv6 address. If ip is an IPv6 address, then wrap ip with square brackets, e.g.: ptcp:6640:[::1].
punix:file

On POSIX, listen on the Unix domain server socket named file for a connection.

On Windows, listen on a local named pipe. A file is created in the path file to mimic the behavior of a Unix domain socket.