title: Is welcoming port the same as listening port?
body: <p>Hi I'm just a newbie in networking,
  just want to ask, is welcoming port of welcoming socket on a server the same as listening port?
  For example, we all know HTTP use port 80, so is port 80 the welcoming port of the web server to initialize TCP's three way handshake? and actual port number of connection socket (for transmission of  http message) can be arbitrary number assigned by the server? </p>