Request for Comments (RFC)

IndustryRFC

Description

The Request for Comments series — the foundational document series of the Internet. RFCs cover every Internet protocol from TCP (RFC 793) and IP (RFC 791) through HTTP (RFC 9110), TLS (RFC 8446), and modern extensions. Despite the name, RFCs at the STD level are formal Internet Standards. RFC numbers are never reused; once published, an RFC is immutable (errors are addressed via new RFCs that obsolete old ones).

Syntax

IETF identifiers come in 5 shapes: RFC '<number>', BCP '<number>', STD '<number>', FYI '<number>', and Internet-Draft '<draft-name>-<version>'. Internet-Drafts are work-in-progress documents with a name like 'draft-giuliano-treedn' and an optional two-digit version suffix. RFCs/BCPs/STDs/FYIs share the same numbering space conceptually but each has its own sub-series index.

Examples 5

RFC 2119

RFC 8174

RFC 791

RFC 9110

RFC 8446

Components Used

IETF Request for Comments (RFC) identifiers are composed of these elements:

Series

Series prefix: RFC, BCP, STD, FYI (or nil for Internet-Drafts)

e.g.RFC

:series

Number

Sequence number within the sub-series (RFC, BCP, STD, FYI)

e.g.2119

:number

Draft Name

Internet-Draft name (e.g. 'draft-giuliano-treedn'), without version suffix

:name

Version

Internet-Draft two-digit version suffix (e.g. '02'), nil when absent

:version

Algebraic Relations

Relations that can involve Request for Comments (RFC) identifiers:

Relation	Description	Syntax	Example
RFC	Standard RFC citation	`RFC <number>`	`RFC 2119`
BCP	Best Current Practice	`BCP <number>`	`BCP 3`
STD	Internet Standard (sub-series)	`STD <number>`	`STD 66`
FYI	For Your Information	`FYI <number>`	`FYI 1`
Internet-Draft	Work-in-progress draft, optional version suffix	`<draft-name>[-<version>]`	`draft-giuliano-treedn-02`

URN Mapping

Patternurn:ietf:[series]:[number]