HTTP Related Protocols

This is a small sample of other Internet transfer protocols and information representation protocols.


The Internet Message Access Protocol, Version 4rev1 (IMAP4rev1) allows a client to access and manipulate electronic mail messages on a server. IMAP4rev1 permits manipulation of remote message folders, called "mailboxes", in a way that is functionally equivalent to local mailboxes. IMAP4rev1 also provides the capability for an offline client to resynchronize with the server.

IMAP4rev1 includes operations for creating, deleting, and renaming mailboxes; checking for new messages; permanently removing messages; setting and clearing flags; [RFC-822] and [MIME-IMB] parsing; searching; and selective fetching of message attributes, texts, and portions thereof. Messages in IMAP4rev1 are accessed by the use of numbers. These numbers are either message sequence numbers or unique identifiers.


RFC 822 defines a message representation protocol which specifies considerable detail about message headers, but which leaves the message content, or message body, as flat ASCII text. MIME redefines the format of message bodies to allow multi-part textual and non-textual message bodies to be represented and exchanged without loss of information. This is based on earlier work documented in RFC 934 and RFC 1049, but extends and revises that work. Because RFC 822 said so little about message bodies, this document is largely orthogonal to (rather than a revision of) RFC 822.

File Transfer Protocol (FTP)

The file transfer protocol currently most used for accessing fairly stable public information over a wide area is "Anonymous FTP". This means the use of the internet File Transfer Protocol without authentication. As the WWW project currently operates for the sake of public information, anonymous FTP is quite appropriate, and WWW can pick up any information provided by anonymous FTP. FTP is defined in RFC 959 which includes material from many previous RFCs. (See also: file address syntax ). Directories are browsed as hypertext. The browser will notice references to files which are in fact accessible as locally mounted (or on DECnet on VMS systems) and use direct access instead.

Network News Protocol

The "Network News Transfer Protocol" (NNTP) is defined in RFC 977 by Kantor and Lampsley. This allows transient news information in the USENET news format to be exchanged over the internet. The format of news articles is defined in RFC 850, Standard for Interchange of USENET Messages by Mark Horton. This in turn refers to the standard RFC 822 which defines the format of internet mail messages. News articles make good examples of hypertext, as articles contain references to other articles and news groups. News groups appear like directories, but more informative.


The Gopher distributed information system uses a lightweight protocol very similar to HTTP. Therefore, it is now included in every WWW client, so that the Gopher world can be browsed as part of the Web. Gopher menus are easily mapped onto hypertext links. It may be that future versions of the Gopher and HTTP protocols will converge.


With the use of the freeWAIS software from CNIDR, the W3 software now accesses WAIS servers directly. WAIS is a variant of the z39.50 protocol. This is being developed from earlier versions which did not have the functionality required for NIR. -- see draft standards documents .

Henrik Frystyk Nielsen
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