Only one. If there was more than one process listening on the same port, then there would be no way of knowing which process incoming data was intended for. -DJ Craig
A computer port is a connection point between a computer and an internal or external device. Its purpose is to identify various applications or processes that are executing on a single computer.
No, Whitney Port is not single.
Port 23
32239
By default it listens on SMTP port 25
Cups uses port 631 by default
Edit the ports.conf file and change the line listen 80 to listen 81 which is, all in all, remarkably straightforward.
port 25
A computer port is a connection point between a computer and an internal or external device. Its purpose is to identify various applications or processes that are executing on a single computer.
Conventionally, an HTTP server listens on port 80. Regardless of the brand of web server that you are running, the server will typically listen for HTTP traffic on port 80 and HTTPS traffic on port 443.
A single port can be configured to listen for UDP or TCP inbound connection requests (or both). Telnet uses TCP. So when you telnet to a specific IP:port, telnet will attempt to make a TCP connection. If there is no TCP listener on the port you specify, then the connection request will be refused. It matters not if you have a UDP listener on the port. Telnet will not be able to establish a connection to a UDP port.
If a network address is thought of as a physical address for a building then a port would be a room within the building. THe function of a port is to allow software to listen for or send out communication that is specifically related to it's function. For example, most internet (http) traffic is on port 80, FTP (File Transfer Protocol) sends and listens on Port 21, other services use other ports. This allows a single computer with a single IP address to be both a web server and a file server.