RFC4949, Internet Security Glossary, Version 2, August 2007 Each entry is preceded by a character -- I, N, O, or D -- enclosed in parentheses, to indicate the type of definition (as is explained further in Section 3):
- "I" for a RECOMMENDED term or definition of Internet origin.
- "N" if RECOMMENDED but not of Internet origin.
- "O" for a term or definition that is NOT recommended for use in IDOCs but is something that authors of Internet documents should know about.
- "D" for a term or definition that is deprecated and SHOULD NOT be used in Internet documents.