Many RFCs are the standards on which the Internet is formed. IMC has prepared a brief introduction to Internet standards that gives a bit more background to RFCs. Some RFCs are not solid standards, but they nonetheless document technologies that are of great value to the Internet and thus should be used as guidelines for implementing Internet mail programs. You may also want to look through the official list of all RFCs to see which RFCs have been made obsolete by newer ones. Not all Internet RFCs are standards.
Internet standards are subject to extensive review and testing.
In addition, B indicates a Best Current Practice, and E indicates Experimental. The official rules for how RFCs are made and how things become standards are stated in RFC 2026 . Because I-Ds are often rough drafts and subject to major changes, they are described in a different document. The IMC has created a separate list of I-Ds relating to Internet Mail . Types of Internet Mail Standards and Protocols Internet mail standards and protocols fall into some broad categories.