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A Request for Comments (RFC) is a publication in a series, from the principal technical development and standards-setting bodies for the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consist ...

Internet
, most prominently the
Internet Engineering Task Force The Internet Engineering Task Force (IETF) is an open standards organization, which develops and promotes voluntary Internet standards, in particular the technical standards that comprise the Internet protocol suite (TCP/IP). It has no formal ...
(IETF). An RFC is authored by individuals or groups of engineers and
computer scientist A computer scientist is a person who has acquired the knowledge of computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques ...

computer scientist
s in the form of a
memorandum A memorandum (abbrev.: memo; from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Throug ...
describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems. It is submitted either for
peer review Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (). It functions as a form of self-regulation by qualified members of a profession within the relevant . Peer review methods ar ...
or to convey new concepts, information, or, occasionally, engineering humor. The IETF adopts some of the proposals published as RFCs as
Internet Standard An Internet Standard in computer network engineering refers to the normative specification of a technology that is appropriate for the Internet. Internet Standards allow interoperation of hardware and software from different sources which allows th ...
s. However, many RFCs are informational or experimental in nature and are not standards. The RFC system was invented by
Steve Crocker Stephen D. Crocker (born October 15, 1944 in Pasadena, California, United States) is the inventor of the Request for Comments series, authoring the first RFC and many more. He attended Van Nuys High School, as did Vint Cerf and Jon Postel. Crocke ...
in 1969 to help record unofficial notes on the development of
ARPANET The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switching In telecommunications, packet switching is a method of grouping data that is transmitted over a digital network into '' packets''. Packets are ...
. RFCs have since become official documents of Internet
specifications A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard. There are different types of technical or engineering specification ...
,
communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system 400px, Communication system A communications system or communication system is a collection of individual telecommunications networ ...
s, procedures, and events. According to Crocker, the documents "shape the Internet's inner workings and have played a significant role in its success", but are not widely known outside the community. Outside of the Internet community, other documents also called ''requests for comments'' have been published in U.S. Federal government work, such as the
National Highway Traffic Safety Administration The National Highway Traffic Safety Administration (NHTSA ) is an agency Agency may refer to: * a governmental or other institution Institutions, according to Samuel P. Huntington, are "stable, valued, recurring patterns of behavior". Ins ...
.


History

The inception of the RFC format occurred in 1969 as part of the seminal
ARPANET The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switching In telecommunications, packet switching is a method of grouping data that is transmitted over a digital network into '' packets''. Packets are ...
project. Today, it is the official publication channel for the Internet Engineering Task Force (IETF), the
Internet Architecture Board The Internet Architecture Board (IAB) is "a committee of the Internet Engineering Task Force The Internet Engineering Task Force (IETF) is an open standards organization A standards organization, standards body, standards developing organi ...
(IAB), and to some extent the global community of computer network researchers in general. The authors of the first RFCs their work and circulated hard copies among the ARPA researchers. Unlike the modern RFCs, many of the early RFCs were actual Requests for Comments and were titled as such to avoid sounding too declarative and to encourage discussion. The RFC leaves questions open and is written in a less formal style. This less formal style is now typical of
Internet Draft An Internet Draft (I-D) is a document published by the Internet Engineering Task Force (IETF) containing preliminary technical specifications, results of computer network, networking-related research, or other technical information. Often, Internet ...
documents, the precursor step before being approved as an RFC. In December 1969, researchers began distributing new RFCs via the newly operational ARPANET. RFC1, titled "Host Software", was written by
Steve Crocker Stephen D. Crocker (born October 15, 1944 in Pasadena, California, United States) is the inventor of the Request for Comments series, authoring the first RFC and many more. He attended Van Nuys High School, as did Vint Cerf and Jon Postel. Crocke ...
of the
University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public university, public Land-grant university, land-grant research university in Los Angeles, California. UCLA’s academic roots were established in 1882 as a teachers college then known ...
(UCLA), and published on April 7, 1969. Although written by Steve Crocker, the RFC had emerged from an early
working group A working group, or working party, is a group of experts working together to achieve specified goals. The groups are domain-specific and focus on discussion or activity around a specific subject area. The term can sometimes refer to an interdis ...

working group
discussion between Steve Crocker, Steve Carr, and
Jeff Rulifson Johns Frederick (Jeff) Rulifson (born August 20, 1941) is an American computer scientist. Early life and education Johns Frederick Rulifson was born August 20, 1941 in Bellefontaine, Ohio. His father was Erwin Charles Rulifson and mother was Virg ...
. In RFC 3, which first defined the RFC series, Crocker started attributing the RFC series to the Network Working Group. Rather than being a formal committee, it was a loose association of researchers interested in the ARPANET project. In effect, it included anyone who wanted to join the meetings and discussions about the project. Many of the subsequent RFCs of the 1970s also came from UCLA, because UCLA is one of the first of what were
Interface Message Processor The Interface Message Processor (IMP) was the packet switching node (networking), node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of Gateway (telecommunications), gateways, whic ...
s (IMPs) on ARPANET. The
Augmentation Research Center SRI International's Augmentation Research Center (ARC) was founded in the 1960s by electrical engineer Douglas Engelbart to develop and experiment with new tools and techniques for collaboration and information processing Information processing ...
(ARC) at
Stanford Research Institute SRI International (SRI) is an American nonprofit organization, nonprofit scientific research, scientific research institute and organization headquartered in Menlo Park, California. The trustees of Stanford University established SRI in 1946 as ...
, directed by
Douglas Engelbart Douglas Carl Engelbart (January 30, 1925 – July 2, 2013) was an engineer Engineers, as practitioners of engineering, are Professional, professionals who Invention, invent, design, analyze, build and test Machine, machines, complex sys ...
, is another of the four first of what were ARPANET
nodes In general, a node is a localized swelling (a "knot") or a point of intersection (a Vertex (graph theory), vertex). Node may refer to: In mathematics *Vertex (graph theory), a vertex in a mathematical graph *Node (autonomous system), behaviour fo ...

nodes
and the source of early RFCs. The ARC became the first network information center (
InterNIC The Network Information Center (NIC), also known as InterNIC from 1993 until 1998, was the organization primarily responsible for Domain Name System The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers ...
), which was managed by
Elizabeth J. Feinler Elizabeth Jocelyn "Jake" Feinler (born March 2, 1931) is an American information scientist. From 1972 until 1989 she was director of the Network Information Systems Center at the SRI International, Stanford Research Institute (SRI International). ...
to distribute the RFCs along with other network information. From 1969 until 1998,
Jon Postel Jonathan Bruce Postel (; August 6, 1943 – October 16, 1998) was an American computer scientist A computer scientist is a person A person (plural people or persons) is a being that has certain capacities or attributes such as reason, mora ...

Jon Postel
served as the RFC
editor Editing is the process of selecting and preparing written Writing is a medium of human communication Communication (from Latin ''communicare'', meaning "to share") is the act of developing Semantics, meaning among Subject (philosoph ...

editor
. On his death in 1998, his obituary was published as RFC 2468. Following the expiration of the original ARPANET contract with the U.S. federal government, the Internet Society, acting on behalf of the IETF, contracted with the Networking Division of the
University of Southern California , mottoeng = "Let whoever earns the palm bear it" , religious_affiliation = Nonsectarian - Methodist Methodism, also called the Methodist movement, is a group of historically related denominations Denomination may refer to: * Religious de ...

University of Southern California
(USC)
Information Sciences Institute The USC Information Sciences Institute (ISI) is a component of the University of Southern California (USC) Viterbi School of Engineering, and specializes in research and development in information processing, computing, and communications techn ...
(ISI) to assume the editorship and publishing responsibilities under the direction of the IAB. Sandy Ginoza joined USC/ISI in 1999 to work on RFC editing, and Alice Hagens in 2005.
Bob Braden Robert Braden (28 January 1934 – 15 April 2018) was an United States, American computer scientist who played a role in the development of the Internet. His research interests included End-to-end principle, end-to-end network protocols, especially ...
took over the role of RFC project lead, while Joyce K. Reynolds continued to be part of the team until October 13, 2006. In July 2007, ''streams'' of RFCs were defined, so that the editing duties could be divided. IETF documents came from IETF working groups or submissions sponsored by an IETF area director from the
Internet Engineering Steering Group The Internet Engineering Task Force (IETF) is an open standards organization, which develops and promotes voluntary Internet standards, in particular the technical standards that comprise the Internet protocol suite (TCP/IP). It has no formal ...
. The IAB can publish its own documents. A research stream of documents comes from the
Internet Research Task Force{{Infobox organization , name = Internet ResearchTask Force , image = Irtf-logo.svg , image_border = , size = 225px , caption = , map = , msize = , mcaption = , abbreviation = IRT ...
(IRTF), and an independent stream from other outside sources. A new model was proposed in 2008, refined, and published in August 2009, splitting the task into several roles, including the RFC Series Advisory Group (RSAG). The model was updated in 2012. The streams were also refined in December 2009, with standards defined for their style. In January 2010 the RFC Editor function was moved to a contractor, Association Management Solutions, with Glenn Kowack serving as interim series editor. In late 2011, Heather Flanagan was hired as the permanent RFC Series Editor. Also at that time, an RFC Series Oversight Committee (RSOC) was created. Requests for Comments were originally produced in non- reflowable text format. In August 2019 the format was changed so that new documents can be viewed optimally in devices with varying display sizes.


Production and versioning

The RFC Editor assigns each RFC a
serial number A serial number is a unique identifier A unique identifier (UID) is an identifier that is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. The concept was formalized early in the development o ...

serial number
. Once assigned a number and published, an RFC is never rescinded or modified; if the document requires amendments, the authors publish a revised document. Therefore, some RFCs supersede others; the superseded RFCs are said to be ''deprecated'', ''obsolete'', or ''obsoleted by'' the superseding RFC. Together, the serialized RFCs compose a continuous historical record of the evolution of Internet standards and practices. The RFC process is documented in RFC 2026 (''The Internet Standards Process, Revision 3''). The RFC production process differs from the
standardization Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization ...
process of formal standards organizations such as
International Organization for Standardization The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is an established norm Norm, the Norm or NORM may refer to: In academic discipline ...
(ISO). Internet technology experts may submit an
Internet Draft An Internet Draft (I-D) is a document published by the Internet Engineering Task Force (IETF) containing preliminary technical specifications, results of computer network, networking-related research, or other technical information. Often, Internet ...
without support from an external institution. Standards-track RFCs are published with approval from the IETF, and are usually produced by experts participating in IETF Working Groups, which first publish an Internet Draft. This approach facilitates initial rounds of peer review before documents mature into RFCs. The RFC tradition of pragmatic, experience-driven, after-the-fact standards authorship accomplished by individuals or small working groups can have important advantages over the more formal, committee-driven process typical of ISO and national standards bodies. Most RFCs use a common set of terms such as "MUST" and "NOT RECOMMENDED" (as defined by RFC 2119 and RFC 8174),
augmented Backus–Naur formIn computer science, augmented Backus–Naur form (ABNF) is a metalanguage based on Backus–Naur form (BNF), but consisting of its own syntax and derivation rules. The motive principle for ABNF is to describe a formal system of a language to be used ...
(ABNF) (RFC 5234) as a meta-language, and simple text-based formatting, in order to keep the RFCs consistent and easy to understand.


Sub-series

The RFC series contains three sub-series for
IETF The Internet Engineering Task Force (IETF) is an open standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization whose primary functi ...
RFCs: BCP, FYI, and STD. Best Current Practice (BCP) is a sub-series of mandatory IETF RFCs not on standards track. For Your Information (FYI) is a sub-series of informational RFCs promoted by the IETF as specified in RFC 1150 (FYI 1). In 2011, RFC 6360 obsoleted FYI 1 and concluded this sub-series. Standard (STD) used to be the third and highest maturity level of the IETF standards track specified in RFC 2026 (BCP 9). In 2011 RFC 6410 (a new part of BCP 9) reduced the standards track to two maturity levels.


Streams

There are four streams of RFCs:
IETF The Internet Engineering Task Force (IETF) is an open standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization whose primary functi ...
, IRTF, IAB, and ''independent submission''. Only the IETF creates BCPs and RFCs on the standards track. An ''independent submission'' is checked by the
IESG The Internet Engineering Task Force (IETF) is an open standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization whose primary functi ...
for conflicts with IETF work; the quality is assessed by an ''independent submission editorial board''. In other words, IRTF and ''independent '' RFCs are supposed to contain relevant info or experiments for the Internet at large not in conflict with IETF work; compare RFC 4846, RFC 5742, and RFC 5744.


Obtaining RFCs

The official source for RFCs on the
World Wide Web The World Wide Web (WWW), commonly known as the Web, is an information system An information system (IS) is a formal, sociotechnical Sociotechnical systems (STS) in organizational development is an approach to complex organizational ...
is the /www.rfc-editor.org/rfc.html RFC Editor Almost any published RFC can be retrieved via a
URL A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network A computer network is a group of computers that use a set of common communication prot ...

URL
of the form http://www.rfc-editor.org/rfc/rfc5000.txt, shown for RFC 5000. Every RFC is submitted as plain
ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding Character encoding is the process of assigning numbers to graphical Graphics (from Greek Greek may refer to: Greece Anything of, ...
text and is published in that form, but may also be available in other formats. For easy access to the metadata of an RFC, including abstract, keywords, author(s), publication date, errata, status, and especially later updates, the RFC Editor site offers a search form with many features. A redirection sets some efficient parameters, example: rfc:5000. The official
International Standard Serial Number An International Standard Serial Number (ISSN) is an eight-digit serial number A serial number is a unique identifier A unique identifier (UID) is an identifier that is guaranteed to be unique among all identifiers used for those objec ...
(ISSN) of the RFC series is 2070–1721.


Status

Not all RFCs are standards. Each RFC is assigned a designation with regard to status within the Internet standardization process. This status is one of the following: ''Informational'', ''Experimental'', ''Best Current Practice'', ''Standards Track'', or ''Historic''. Each RFC is static; if the document is changed, it is submitted again and assigned a new RFC number.


Standards Track

Standards-track documents are further divided into ''Proposed Standard'' and ''Internet Standard'' documents. Only the IETF, represented by the
Internet Engineering Steering Group The Internet Engineering Task Force (IETF) is an open standards organization, which develops and promotes voluntary Internet standards, in particular the technical standards that comprise the Internet protocol suite (TCP/IP). It has no formal ...
(IESG), can approve standards-track RFCs. If an RFC becomes an Internet Standard (STD), it is assigned an STD number but retains its RFC number. The definitive list of Internet Standards is the Official Internet Protocol Standards. Previously STD 1 used to maintain a snapshot of the list. When an Internet Standard is updated, its STD number stays the same, now referring to a new RFC or set of RFCs. A given Internet Standard, STD ''n'', may be RFCs ''x'' and ''y'' at a given time, but later the same standard may be updated to be RFC ''z'' instead. For example, in 2007 RFC 3700 was an Internet Standard—STD 1—and in May 2008 it was replaced with RFC 5000, so RFC 3700 changed to ''Historic'', RFC 5000 became an Internet Standard, and STD 1 is RFC 5000. RFC 5000 is replaced by RFC 7100, updating RFC 2026 to no longer use STD 1. (Best Current Practices work in a similar fashion; BCP ''n'' refers to a certain RFC or set of RFCs, but which RFC or RFCs may change over time).


Informational

An ''informational'' RFC can be nearly anything from April 1 jokes to widely recognized essential RFCs like
Domain Name System The Domain Name System (DNS) is the hierarchical and Decentralised system, decentralized naming system used to identify computers, Internet#Applications_and_services, services, and other resources reachable through the internet or other intern ...

Domain Name System
Structure and Delegation (RFC 1591). Some informational RFCs formed the FYI sub-series.


Experimental

An ''experimental'' RFC can be an IETF document or an individual submission to the RFC Editor. A draft is designated experimental if it is unclear the proposal will work as intended or unclear if the proposal will be widely adopted. An experimental RFC may be promoted to standards track if it becomes popular and works well.


Best Current Practice

The
Best Current Practice A Best Current Practice (BCP) is a ''de facto'' level of performance in engineering and information technology. It is more flexible than a Technical standard, standard, since techniques and tools are continually evolving. The Internet Engineering ...
subseries collects administrative documents and other texts which are considered as official rules and not only ''informational'', but which do not affect ''over the wire data''. The border between standards track and BCP is often unclear. If a document only affects the Internet Standards Process, like BCP 9, or IETF administration, it is clearly a BCP. If it only defines rules and regulations for
Internet Assigned Numbers Authority The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, Autonomous system (Internet), autonomous system number allocation, DNS root zone, root zone management in the Domain Name Sys ...
(IANA) registries it is less clear; most of these documents are BCPs, but some are on the standards track. The BCP series also covers technical recommendations for how to practice Internet standards; for instance, the recommendation to use source filtering to make DoS attacks more difficult (RFC 2827: "''Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing''") is /tools.ietf.org/html/bcp38 BCP 38


Historic

A ''historic'' RFC is one that the technology defined by the RFC is no longer recommended for use, which differs from "Obsoletes" header in a replacement RFC. For example, RFC 821 (
SMTP The Simple Mail Transfer Protocol (SMTP) is an internet standard An Internet Standard in computer network engineering refers to the normative specification of a technology that is appropriate for the Internet. Internet Standards allow interoper ...
) itself is obsoleted by various newer RFCs, but SMTP itself is still "current technology", so it is not in "Historic" status. However, since BGP version 4 has entirely superseded earlier BGP versions, the RFCs describing those earlier versions, such as RFC 1267, have been designated historic.


Unknown

Status ''unknown'' is used for some very old RFCs, where it is unclear which status the document would get if it were published today. Some of these RFCs would not be published at all today; an early RFC was often just that: a simple Request for Comments, not intended to specify a protocol, administrative procedure, or anything else for which the RFC series is used today.


Copyright

The general rule is that original authors (or their employers, if their employment conditions so stipulate) retain copyright unless they make an explicit transfer of their rights. An independent body, the IETF Trust, holds the copyright for some RFCs and for all others it is granted a license by the authors that allows it to reproduce RFCs. The
Internet Society The Internet Society (ISOC) is an American nonprofit organization A nonprofit organization (NPO), also known as a non-business entity, not-for-profit organization, or nonprofit institution, is a legal entity organized and operated for a col ...
is referenced on many RFCs prior to RFC4714 as the copyright owner, but it transferred its rights to the IETF Trust.


See also

*
April Fools' Day RFC April is the fourth month of the year in the Gregorian calendar The Gregorian calendar is the calendar used in most of the world. It was introduced in October 1582 by Pope Gregory XIII as a minor modification of the Julian calendar, r ...
*
Best Current Practice A Best Current Practice (BCP) is a ''de facto'' level of performance in engineering and information technology. It is more flexible than a Technical standard, standard, since techniques and tools are continually evolving. The Internet Engineering ...
*
Internet Experiment NoteAn Internet Experiment Note (IEN) is a sequentially numbered document in a series of technical publications issued by the participants of the early development work groups that created the precursors of the modern Internet The Internet (Ca ...
* List of RFCs


References


External links

* /www.rfc-editor.org/ RFC Editor* /www.rfc-editor.org/rfc.html RFC Database* /www.rfc-editor.org/errata.php RFC Errata* /www.rfc-editor.org/rfcfaq.html RFC Frequently Asked Questions* /www.rfc-editor.org/rfc-index2.html RFC Index(text) * /www.rfc-editor.org/search/standards.php Official Internet Protocol Standards* /www.ietf.org/rfc.html IETF's RFC page* /tools.ietf.org/rfc/ RFC Index(HTML) With the text of each RFC, also mentions what other RFCs this one "updates" or is "updated by". {{Authority control Computer-related introductions in 1969