RFCs - The Internet's "Constitution" That Anyone Can Read
RFCs (Request for Comments) are the documents that define the technical standards of the Internet. HTTP, TCP/IP, DNS, TLS, BGP - virtually every protocol that makes up the Internet is published as an RFC. As of 2026, over 9,900 RFCs have been issued, and all of them are freely available for anyone to read.
But the world of RFCs isn't all dry technical documents. April Fools' joke RFCs, ASCII art diagrams, poetically written specifications - it's a unique world filled with the humor and culture of engineers.
"Request for Comments" - The Origin of the Name
The name RFC traces back to the humility of Steve Crocker, who wrote the first RFC (RFC 1) in 1969. At the time a graduate student at UCLA, Crocker was documenting protocol specifications for ARPANET (the precursor to the Internet) and framed it as "not an official standard, but an informal memo requesting comments (Request for Comments)."
He chose the modest name "document requesting opinions" rather than an authoritative "standard specification" to avoid intimidating other researchers and to encourage open discussion. This spirit has been carried forward for over 50 years and is reflected in the IETF's motto: "rough consensus and running code." The same collaborative process produced the RFCs behind today's VPN protocols, including WireGuard and IPsec.
Legendary Joke RFCs
The IETF has a tradition of publishing joke RFCs every April 1st.
RFC 1149 - IP over Avian Carriers (1990)
A specification for transmitting IP datagrams using carrier pigeons. "Avian carriers" physically transport packets, and the recipient reads the data at the destination. Written as a joke, but in 2001, a Norwegian Linux user group actually executed a ping via carrier pigeon, reporting an RTT of approximately 1-2 hours and a packet loss rate of 55%.
RFC 2324 - HTCPCP (1998)
A protocol for controlling coffee pots. This is the RFC that defined HTTP status code 418 "I'm a teapot."
RFC 6921 - Design Considerations for Faster-Than-Light Communication (2013)
An RFC that "seriously" asks what would become of TCP/IP if we had a link that carried information faster than light. Packets would arrive before they were sent, so the round-trip time goes negative and both retransmission timers and packet ordering lose their footing. The premise ignores physics, yet it lays bare how much our protocols lean on something as ordinary as causes coming before effects.
RFC 8565 - Hypertext Jeopardy Protocol (2019)
On the American quiz show Jeopardy, contestants are shown the answer first and have to supply the question that fits it. The Hypertext Jeopardy Protocol brings that rule to HTTP: the client sends a response, and the server answers with the request that would have produced it, swapping the two roles entirely.
The ASCII Art Culture of RFCs
RFCs have traditionally been written in plain text format. When diagrams were needed, authors had to draw them using only ASCII characters. This constraint gave rise to the distinctive ASCII art culture of RFCs.
+--------+ +--------+ +--------+ | Client |--->| Server |--->| DB | +--------+ +--------+ +--------+
Since RFC 8650 in 2019, RFCs have transitioned to an XML-based format (RFC XML v3) that supports SVG images and rich formatting. However, many authors still prefer using ASCII art.
RFCs That Affect Every Internet User
Joke RFCs are fun, but the essence of RFCs is the standardization of the Internet's foundational technologies. Right now, as you read this article, the following RFCs are at work.
- RFC 791 (1981): IPv4. The basic specification for IP addresses
- RFC 793 (1981): TCP. The foundation for reliable data transfer
- RFC 1035 (1987): DNS. Domain name resolution
- RFC 2616 → RFC 9110 (2022): HTTP. The protocol for web communication
- RFC 8446 (2018): TLS 1.3. The latest standard for encrypted communication
- RFC 4271 (2006): BGP. Internet routing
RFC Numbering and Jon Postel
RFC numbers are simple sequential numbers assigned in order of publication. The person who managed this numbering for many years was Jon Postel. From 1969 until his death in 1998, Postel served as RFC Editor, managing the publication of all RFCs for approximately 30 years.
Postel is also known for the "Robustness Principle" (Postel's Law). The principle stated in RFC 793 - "be conservative in what you do, be liberal in what you accept from others" - is widely cited as a design philosophy for Internet protocols.
Summary
RFCs are both the technical standards of the Internet and the cultural heritage of the engineering community. IP communication via carrier pigeons, the teapot status code, ASCII art diagrams - this humor is proof that the Internet was built through "consensus and cooperation."
All RFCs are freely available at rfc-editor.org. Starting with the IP address specification (RFC 791) that you can verify with IP Check-san might be an interesting place to begin reading.
Related Glossary Terms
Frequently Asked Questions
What is an RFC?
RFC stands for Request for Comments. RFCs are the official documents that define internet standards, protocols, and best practices. Published by the IETF, they range from foundational protocols like TCP/IP to informational documents and even humorous April Fools' jokes.
What are joke RFCs?
Since 1978, the IETF has published humorous RFCs on April 1st. Famous examples include RFC 1149 (IP over Avian Carriers, describing internet protocol via carrier pigeons) and RFC 2324 (Hyper Text Coffee Pot Control Protocol, which gave us the 418 I'm a teapot status code).
What is Postel's Law?
Postel's Law, also known as the Robustness Principle, states: 'be conservative in what you do, be liberal in what you accept from others.' Formulated by Jon Postel in RFC 793, it guided early internet protocol design by encouraging implementations to be strict in their output but tolerant of minor deviations in input.