Wellknown, registered, dynamic and private ports

Posted on by

In computer networks a port is a communications endpoint in a computer’s host operating system. A port is associated with an IP address of the host, as well as the type of protocol (TCP, UDP, SC)used for communication. A port is identified for each address and protocol by a 16-bit number, commonly known as the port number which completes the destination address for a communications session. Different IP addresses or protocols may use the same port number for communications.

The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for the global coordination of  Internet protocol resources which includes the registration of commonly used port numbers.

The port numbers are divided into three ranges :

  • well-known ports (0 – 1023
  • registered ports (1024 – 49151)
  • dynamic or private ports (49152 -65535)

Examples :

Well-known ports :

  • 1 : Echo
  • 20 & 21 : File Transfer Protocol (FTP)
  • 23 : Telnet remote login service
  • 25 : Simple Mail Transfer Protocol (SMTP)
  • 43  : Whois
  • 53 : Domain Name System (DNS) service
  • 80 : Hypertext Transfer Protocol (HTTP) used in the World Wide Web
  • 110 : Post Office Protocol (POP3)
  • 143 : Internet Message Access Protocol (IMAP)
  • 194 : IRC
  • 443 : HTTP Secure (HTTPS)
  • 554 : RTSP
  • 636 : LDAP

Registered ports :

  • 1234 : VLC
  • 1220 : Qicktime Server Admin
  • 1935 : RTMP
  • 2948, 2949 : MMS
  • 3306 : MySQL
  • 5004, 5005 : RTP
  • 5060, 5061 : SIP
  • 5269 : XMPP
  • 5500, 5800, 5900 : VNC
  • 8008 : HTTP Alternate
  • 25565 : MySQL

Dynamic and private ports :

The dynamic port numbers (also known as the private port numbers) are the port numbers that are available for use by any application to use in communicating with any other application, using the Internet’s Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP).

More informations about computer ports are available at the following links :