RFC 20 is a document in the series of Request for Comments (RFC) published by the Internet Engineering Task Force (IETF) that provides a specification or commentary on aspects of the Internet and networking technologies. This particular RFC is titled “The TCP Port Number Assignment Procedure” and was published in 1969.

• Port Number Assignment: RFC 20 outlines the procedure for assigning Transmission Control Protocol (TCP) port numbers, which are essential for routing and managing network traffic. It describes how port numbers are used to distinguish different services and applications running on a networked device.
• Standardization: The document provides a framework for ensuring that port numbers are assigned consistently and transparently, helping avoid conflicts and ensuring that network services can be reliably accessed.

• Early Networking: RFC 20 was published during the early days of the Internet, a period marked by rapid development and experimentation with network protocols. It reflects the efforts to standardize practices as the Internet began to evolve.
• Legacy: While RFC 20 is a foundational document, it has been superseded by more recent standards and procedures as the Internet has grown and become more complex. The principles laid out in RFC 20, however, continue to influence how port numbers are managed.

• Port Number Management: For current procedures and guidelines on port number assignment, refer to later RFCs and standards that have built upon the initial framework established in RFC 20. Modern protocols and documentation offer more detailed and updated information on port assignments.
• Additional Reading: For further information on port number assignment and related topics, consult updated RFCs and Internet standards that provide comprehensive guidelines and best practices.

RFC 20 represents an early but important effort to standardize TCP port number assignment, laying the groundwork for network service management. Although superseded by newer standards, its legacy continues to impact how port numbers are assigned and managed in modern networking.

• https://tools.ietf.org/html/rfc20
• https://en.wikipedia.org/wiki/Request_for_Comments