Anonymous SASL Mechanism (RFC2245)
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
As plaintext login commands are not permitted in new IETF protocols, a new way to provide anonymous login is needed within the context of the SASL [SASL] framework. [STANDARDS-TRACK]
Network Working Group C. Newman Request for Comments: 2245 Innosoft Category: Standards Track November 1997
Anonymous SASL Mechanism
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1997). All Rights Reserved.
It is common practice on the Internet to permit anonymous access to various services. Traditionally, this has been done with a plain text password mechanism using "anonymous" as the user name and optional trace information, such as an email address, as the password. As plaintext login commands are not permitted in new IETF protocols, a new way to provide anonymous login is needed within the context of the SASL [SASL] framework.
1. Conventions Used in this Document
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as defined in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS].
2. Anonymous SASL mechanism
The mechanism name associated with anonymous access is "ANONYMOUS". The mechanism consists of a single message from the client to the server. The client sends optional trace information in the form of a human readable string. The trace information should take one of three forms: an Internet email address, an opaque string which does not contain the ’@’ character and can be interpreted by the system administrator of the client’s domain, or nothing. For privacy reasons, an Internet email address should only be used with permission from the user.
Newman Standards Track [Page 1]
RFC 2245 Anonymous SASL Mechanism November 1997
A server which permits anonymous access will announce support for the ANONYMOUS mechanism, and allow anyone to log in using that mechanism, usually with restricted access.
The formal grammar for the client message using Augmented BNF [ABNF] follows.
message = [email / token]
TCHAR = %x20-3F / %x41-7E ;; any printable US-ASCII character except ’@’
email = addr-spec ;; as defined in [IMAIL], except with no free ;; insertion of linear-white-space, and the ;; local-part MUST either be entirely enclosed in ;; quotes or entirely unquoted
token = 1*255TCHAR
Here is a sample anonymous login between an IMAP client and server. In this example, "C:" and "S:" indicate lines sent by the client and server respectively. If such lines are wrapped without a new "C:" or "S:" label, then the wrapping is for editorial clarity and is not part of the command.
Note that this example uses the IMAP profile [IMAP4] of SASL. The base64 encoding of challenges and responses, as well as the "+ " preceding the responses are part of the IMAP4 profile, not part of SASL itself. Newer profiles of SASL wil...