However, many unofficial uses of both well-known and registered port numbers occur in practice. The Internet Assigned Numbers Authority (IANA) is responsible for maintaining the official assignments of port numbers for specific uses. They usually use port numbers that match the services of the corresponding TCP or UDP implementation, if they exist. The Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) only need one port for duplex, bidirectional traffic. This is a list of TCP and UDP port numbers used by protocols for operation of network applications. ( Learn how and when to remove this template message) ( October 2016) ( Learn how and when to remove this template message) Unsourced or poorly sourced material may be challenged or removed. Please help improve this article by adding citations to reliable sources that describe the examples' significance, and by removing less pertinent examples. This article gives self-sourcing popular culture examples without describing their significance in the context of the article.
