What are RFCs - Requests for Comments?

RFCs (Requests for Comments) are documents that essentially define the Internet. They establish and share standards and protocols, ensuring everyone's systems can talk to each other.

You will undoubtedly hear about them when you study for exams such as the Cisco CCNA or Network+. Most commonly, when it comes to IP addressing, but as of today, November 8, 2024, there are over 9,000 RFCs published. Many were never adopted for a number of reasons, and others have been replaced over the years. This number is constantly growing as the internet evolves and new technologies emerge. The RFC Editor website (www.rfc-editor.org) is the best place to find the most up-to-date count.

The RFC Editor maintains this website and is the official repository for all published RFCs.

You can search for RFCs by number, keyword, or topic and access the full text of each document.

RFC Breakdown

Establishment and Purpose:

While the RFC process has evolved and is now managed by the IETF, the very first RFCs can be attributed to Steve Crocker. In 1969, Crocker was a researcher at UCLA working on the ARPANET. He started writing these “Requests for Comments” as a way to share notes and ideas with other researchers involved in the project. It was a very informal system at first, simply a way to document their ongoing work. However, it quickly became an essential tool for collaboration and standardization as the ARPANET grew.

So, while the RFC system has become much more formalized over the years, Steve Crocker is recognized as the person who initiated this vital process that underpins the Internet today

Early Days: RFCs started in 1969 as a way for researchers to share notes about the ARPANET (the internet's predecessor).
Formalization: The Internet Engineering Task Force (IETF) now manages the process.
Standardization: RFCs propose, define, and document internet protocols, best practices, and even experimental ideas.

Who Uses RFCs?

RFCs are used by a wide range of people who are involved in the internet and computer networking. Here are some of the key groups:

Engineers: Network engineers, software engineers, and hardware engineers rely on RFCs to design, develop, and implement Internet technologies. They use RFCs to ensure interoperability between different systems and to follow established standards.
Developers: Software developers use RFCs to create applications that interact with the internet, such as web browsers, email clients, and chat programs. RFCs provide the specifications for protocols like HTTP, TCP/IP, and SMTP, which are essential for these applications to function.

Researchers: Researchers in computer science and networking use RFCs to stay informed about the latest developments in internet technology. They also contribute to the RFC process by proposing new standards and protocols.
Network Operators: People who manage and maintain networks, such as internet service providers (ISPs), use RFCs to configure their equipment and ensure their networks operate efficiently and securely.
Standards Organizations: Organizations like the IETF and the Internet Architecture Board (IAB) use RFCs as the basis for Internet standards. They oversee the RFC process and ensure that RFCs are technically sound and meet the needs of the Internet community.
Students: Students studying computer science, networking, or related fields use RFCs to learn about the fundamental principles of the internet and how it works.

In essence, anyone involved in building, maintaining, or using the internet can benefit from understanding and utilizing RFCs. They are a vital resource for ensuring that the internet continues to function as a global, interconnected network.

Top 10 Important RFCs for IT Students:

There are a few must-know RFCs you should study. They will crop up time and time again in IT exams or technical interviews. While reading an entire RFC would prove tiresome, to say the least, knowing what they are about is important.

RFC 791 (Internet Protocol): Defines the fundamental IP addressing system and how data is packetized and routed across the internet.
RFC 793 (Transmission Control Protocol): Works with IP to ensure reliable data delivery, managing how data is sent, received, and acknowledged.
RFC 1034/1035 (Domain Name System): Establishes the hierarchical system that translates human-readable domain names (like [invalid URL removed]) into IP addresses.
RFC 1918 (Address Allocation for Private Internets): Reserves IP address ranges for private networks (like your home Wi-Fi), enabling devices to communicate without conflicting with public internet addresses.
RFC 2616 (Hypertext Transfer Protocol — HTTP/1.1): Defines how web browsers communicate with web servers, including requests, responses, and data formatting.
RFC 2821 (Simple Mail Transfer Protocol): Specifies how email is sent and relayed between mail servers.
RFC 4251 (The Secure Shell (SSH) Protocol Architecture): Establishes secure connections for remote login and command execution, crucial for system administration.
RFC 5322 (Internet Message Format): Defines the structure of email messages, including headers, body content, and attachments.
RFC 6749 (The OAuth 2.0 Authorization Framework): Enables secure delegated access to web resources, allowing users to grant third-party applications limited access to their accounts without sharing passwords.
RFC 7231 (Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content): Further refines HTTP, defining how web servers should handle requests and responses for different types of content.

How These RFCs Affect Everyday Users:

If you were ever asked by a non-technical person if they are important, then you could tell them that they are essential for today's modern internet. Even though most people have never heard of them, we do need them. RFCs underpin the core functions of the internet. They allow you to:

Browse websites: RFCs 2616 and 7231 define how web pages are requested and displayed.
Send emails: RFCs 2821 and 5322 ensure your emails are delivered correctly.
Connect to Wi-Fi: RFC 1918 allows your home network to function without interfering with the wider internet.
Use secure online services: RFC 4251 (SSH) and 6749 (OAuth 2.0) to protect your data and privacy.