RFC977[1] defines the NNTP protocol and  was released over
    a decade ago. Since then, NNTP has become one of the most
    popular protocols in use on the Internet. Many implementations
    of the protocol have been created on many different platforms
    and operating systems. With the growth in use of the
    protocol, work began on a revision to NNTP in 1991, but
    that work did not result in a new standard protocol
    specification. However, many ideas from that working group
    did find their way into many implementations of NNTP.
    Additionally, many other extensions, often created by
    newsreader authors, are also in use. This document will capture
    and define all known extensions to NNTP available in official
    NNTP server releases of some type as of this writing. Where
    possible, the server software first implementing a particular
    extension will be noted. It is the hope of the author that
    using this document in tandem with RFC977 will limit the
    addition of new extensions that essentially do the same thing.
    Software developers may wish to use this document and others[2]
    as a resource for the  development of new software.

    This document does not specify an Internet Standard of any
    kind.  It only attempts to document current practices.
    While this document may clarify some ambiguity in RFC977,
    RFC977 should be regarded as authoritative in all cases.
    There are some implementations that are not strictly RFC977
    compliant and where necessary, these deviations from the
    standard will be noted. This document does reflect the work of
    the IETF NNTP-EXT working group chaired by Ned Freed and Stan
    Barber.

    This document is provided to help implementers have a uniform source
    of information about extensions, however, it is important for any
    prospective implementer to understand that the extensions listed
    here are NOT part of any current standard for NNTP. In fact, some
    of the ones listed in this document should not be included in new
    NNTP implementations as they should no longer be used modern NNTP
    environments. Such commands should be considered historic and are
    documented as such in this document.

    Extensions fall into three categories: transport, newsreader
    and other. Transport extensions are additions to the NNTP
    specification that were made specifically to move news
    articles from one server to another server. Newsreader
    extensions are additions to the NNTP specification that
    were made to assist NNTP clients in selecting and retrieving
    news articles from servers. Other extensions to the NNTP
    specification are those which did not specifically fall
    into either of the other two categories. Examples of other
    extensions include authentication and time-of-day extensions.


    For each command, the format of section 3 of RFC977 will be used.