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. Once submitted, accepted, and published, an RFC cannot be changed. Errata may be submitted, which are published separately. More significant changes require a new submission which will receive a new serial 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 (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 was an Internet Standard—STD 1—and in May 2008 it was replaced with , so changed to
Historic, became an Internet Standard, and STD 1 is . is replaced by , updating 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 Structure and Delegation (). 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 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 (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 (: "
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, (
SMTP) 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 , 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==