As its official home page puts it, the “Request for Comments” “contains technical and organizational notes about the Internet. They cover many aspects of computer networking, including protocols, procedures, programs, and concepts, as well as meeting notes, opinions, and occasional humor.”
Each RFC is derived from a series of publications that engineers and Internet subject matter experts submit to the Internet Engineering Task Force (IETF). RFCs are primarily used to develop a standard network protocol, a function of it, or any feature related to network communication.
RFCs arose as a result of standardizing communication through computer networks because, in the beginning, each manufacturer had its proprietary network protocols, and consequently, there were many protocols for the same purpose. This circumstance affected the interconnection of software and hardware from different manufacturers.
All standard network protocols are defined with an RFC, which does not occur with proprietary protocols. Each RFC consists of a number and is published as a standard after several exhaustive revisions. An RFC cannot be repeated, nor is it allowed to be deleted; absolutely all of them remain for record-keeping regardless of whether they are obsolete. No more comments or changes are allowed when the final version has been published. Comments and changes are only allowed through a subsequent RFC that replaces the previous one (new version or extension of the standard).