What Is an RFC? | RFC Editor

RFCs (Requests for Comments) are documents that describe Internet Standards, technical specifications, protocols, procedures, research, and other information related to the Internet and Internet-connected systems. The RFC Series is the archival publication series for Internet technical specifications and related documents.
The first RFC was written in 1969 by Steve Crocker to organize notes related to the development of ARPANET, which paved the way for the modern Internet. Later RFCs established many of the technical foundations of the Internet itself. Today, people from around the world continue to develop RFCs to document technical work, share information, and standardize Internet technologies.
Not every RFC is an Internet Standard. RFCs can have different statuses and can be published through several different streams. Understanding this information, along with the relationships between RFCs, can help you determine what a particular RFC represents and how it should be read.
Once an RFC is published, its contents do not change. If a specification needs to be changed, the change is published in another RFC. Relationships between RFCs, including updates and obsoletions, are recorded in the RFC metadata. Errata may also be submitted to document errors found after publication.
Anyone is welcome to participate in the creation of RFCs. You can join a working group in your area of interest by subscribing to the mailing list, participating in discussions, and contributing to the Internet-Drafts that may one day be published as an RFC.
RFCs use terminology and conventions that may not be familiar to every reader. Before relying on an RFC, it is useful to look at its metadata as well as the document itself. In particular, you should check its status, publication stream, whether the RFC has been obsoleted or updated, and whether any errata have been reported.
The following sections explain some of the most important information you will encounter when reading an RFC.
An RFC's stream identifies the process through which the document was produced. There are five RFC streams:
RFCs that were published before any stream existed are labelled "Legacy Stream" in place of a stream name.
An RFC's status tells you what kind of document it is. You should not assume that something is an Internet Standard simply because it has been published as an RFC.
An RFC's status can also change over time. See RFC Status Changes for more information.
Standards Track RFCs use the following Statuses:
Other RFC Statuses are:
Some RFCs are also assigned identifiers in an RFC subseries. There are two current subseries: STD (Internet Standard) and BCP (Best Current Practice). Not every RFC belongs to a subseries.
A subseries identifier provides a stable way to identify an Internet Standard or Best Current Practice even when the RFCs that define it change. When an RFC in a subseries is obsoleted, it can be replaced by a newer RFC while the STD or BCP identifier remains the same.
This means that an STD or BCP number and an RFC number serve different purposes: an RFC number permanently identifies a particular published document, while an STD or BCP identifier can continue to identify a standard or practice as its defining RFCs change.
RFCs form a large body of related documents, and specifications often develop over time. Because the text of a published RFC never changes, revisions and replacements are published as new RFCs.
You may see the following relationships:
When you are trying to determine the current specification for a protocol or technology, checking these relationships is an important part of reading an RFC.
Errors discovered after an RFC is published are handled through the RFC Series errata process rather than by changing the published RFC.
When an RFC has reported errata, they are listed in the Errata section of the sidebar on the RFC's page. Errata with a Verified status have been reviewed and determined to be accurate. See the RFC Errata page for more information about the process.
Errata are not incorporated into the TXT, PDF, or XML versions of an RFC. They appear in the display version on this site and in the downloadable HTML version that specifically includes errata.
If you are using an RFC to implement a protocol or need precise technical information, it is a good idea to check for verified errata.
Many RFCs use certain capitalized words to indicate requirement levels. When used as defined by RFC 2119 and RFC 8174, these words have specific meanings. You will see boilerplate in the text of the RFC when these apply:
RFCs have documented the development of Internet technology since 1969. Because published RFCs are never changed or removed from the series, the collection also provides a permanent historical record of the development of the Internet.
For more about the history of RFCs and the RFC Series, see:
The official International Standard Serial Number (ISSN) of the RFC Series is 2070-1721.
Last updated 3 months ago, on 11 August 2026.
rfc-editor.org is maintained by the Internet Engineering Task Force