As per Relevance of the word mechanism, we have this rfc below:
Network Working Group R.
Request for Comments: 2384 QUALCOMM,
Category: Standards Track August 1998
POP URL
Status of this
This document specifies an Internet standards track protocol for
Internet community, and requests discussion and suggestions
improvements. Please refer to the current edition of the "
Official Protocol Standards" (STD 1) for the standardization
and status of this protocol. Distribution of this memo is unlimited
Copyright
Copyright (C) The Internet Society (1998). All Rights Reserved
1.
[POP3] is a widely-deployed mail access protocol. Many
access POP3 message stores, and thus need POP3
information. Since there are multiple configuration elements
are required in order to access a mailbox, a single
representation is convenient
A POP3 mailbox (like an [IMAP4] mailbox) is a network resource,
URLs are a widely-supported generalized representation of
resources
A means of specifying a POP3 mailbox as a URL will likely be
in many programs and protocols. [ACAP] is one case where a
encapsulation of elements required to access network services
needed. For example, an [IMAP4] message store is usually
in ACAP datasets as an [IMAP-URL].
This memo defines a URL scheme for referencing a POP mailbox
2. Conventions Used in this
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY
in this document are to be interpreted as defined in "Key words
use in RFCs to Indicate Requirement Levels" [KEYWORDS].
Gellens Standards Track [Page 1]
RFC 2384 POP URL Scheme August 1998
3. POP
The POP URL scheme designates a POP server, and optionally a
number, authentication mechanism, authentication ID, and/
authorization ID
The POP URL follows the common Internet scheme syntax as defined
RFC 1738 [BASIC-URL] except that clear text passwords are
permitted. If : is omitted, the port defaults to 110.
The POP URL is described using [ABNF] in Section 8.
A POP URL is of the general form
pop://;auth=@:
Where , , and are as defined in RFC 1738, and
or all of the elements, except "pop://" and , may be omitted
4. POP User Name and Authentication
An authorization (which mailbox to access) and authentication (
password to check against) identity (referred to as "user name"
simplicity) and/or authentication mechanism name may be supplied
These are used in a "USER", "APOP", "AUTH" [POP-AUTH], or
command after making the connection to the POP server. If the
doesn't supply an authentication identifier, the program
the POP URL SHOULD request one from the user
An authentication mechanism can be expressed by adding ";AUTH=
auth-type>" to the end of the user name. If the
mechanism name is not preceded by a "+", it is a SASL POP [SASL
mechanism. If it is preceded by a "+", it is either "APOP" or
extension mechanism
When an is specified, the client SHOULD
appropriate credentials from that mechanism and use the "AUTH",
"APOP", or extension command instead of the "USER" command. If
user name is specified, one SHOULD be obtained from the mechanism
requested from the user as appropriate
The string ";AUTH=*" indicates that the client SHOULD select
appropriate authentication mechanism. It MAY use any
supported by the POP server
If an other than ";AUTH=*" is specified, the
SHOULD NOT use a different mechanism without explicit
permission
Gellens Standards Track [Page 2]
RFC 2384 POP URL Scheme August 1998
If a user name is included with no authentication mechanism,
";AUTH=*" is assumed
Since URLs can easily come from untrusted sources, care must be
when resolving a URL which requires or requests any sort
authentication. If authentication credentials are supplied to
wrong server, it may compromise the security of the user's account
The program resolving the URL should make sure it meets at least
of the following criteria in this case
(1) The URL comes from a trusted source, such as a referral
which the client has validated and trusts according to site policy
Note that user entry of the URL may or may not count as a
source, depending on the experience level of the user and
policy
(2) Explicit local site policy permits the client to connect to
server in the URL. For example, if the client knows the site
name, site policy may dictate that any hostname ending in that
is trusted
(3) The user confirms that connecting to that domain name with
specified credentials and/or mechanism is permitted
(4) A mechanism is used which validates the server before
potentially compromising client credentials
(5) An authentication mechanism is used which will not
information to the server which could be used to compromise
connections
A URL containing ";AUTH=*" should be treated with extra care since
might fall back on a weaker security mechanism. Finally, clients
discouraged from using a plain text password as a fallback
";AUTH=*" unless the connection has strong encryption (e.g., a
length of greater than 56 bits).
Note that if unsafe or reserved characters such as " " or ";"
present in the user name or authentication mechanism, they MUST
encoded as described in RFC 1738 [BASIC-URL].
5. Relative POP
Relative POP URLs are not permitted
Gellens Standards Track [Page 3]
RFC 2384 POP URL Scheme August 1998
6. Multinational
Since 8-bit characters are not permitted in URLs, [UTF8]
are encoded as required by the URL specification [BASIC-URL].
7.
The following examples demonstrate how a POP client program
translate various POP URLs into a series of POP commands.
sent from the client to the server are prefixed with "C:",
responses sent from the server to the client are prefixed with "S:".
The URL
Results in the following client commands
password from user
S: +OK POP3 server ready <1896.697170952@mailsrv.qualcomm.com
C: USER
S: +
C: PASS
S: +OK rg's mailbox has 2 messages (320 octets
The URL
Results in the following client commands
requests password from user
S: +OK POP3 server ready <1896.697170952@mail.eudora.com
C: APOP rg c4c9334bac560ecc979e58001b3e22
S: +OK mailbox has 1 message (369 octets
The URL
Results in the following client commands
S: +OK POP3 server ready <1896.697170952@foo.bar
C: AUTH SCRAM-MD5 AGNocmlzADx0NG40UGFiOUhCMEFtL1FMWEI3
Gellens Standards Track [Page 4]
RFC 2384 POP URL Scheme August 1998
Fub3IuaW5ub3NvZnQuY29tPg==
S: + dGVzdHNhbHQBAAAAaW1hcEBlbGVhbm9yLmlubm9zb2Z0
aGNOWmxSdVBiemlGcCt2TFYrTkN
C: AQAAAMg9jU8CeB4KOfk7sUhSQPs
S: + U0odqYw3B7XIIW0oSz65OQ==
C
S: +OK mailbox has 1 message (369 octets
8. ABNF for POP URL
The POP URL scheme is described using [ABNF]:
achar = uchar / "&" / "=" / "~"
; see [BASIC-URL] for "uchar"
auth = ";AUTH=" ( "*" / enc-auth-type )
enc-auth-type = enc-sasl / enc-
enc-ext = "+" ("APOP" / 1*achar
;APOP or encoded extension mechanism
enc-sasl = 1*
;encoded version of [SASL] "auth_type
enc-user = 1*
;encoded version of [POP3]
pop-url = "pop://"
server = [user-auth "@"]
;See [BASIC-URL] for "hostport"
user-auth = enc-user [auth
9. Security
Security considerations discussed in the [POP3] specification and
[BASIC-URL] specification are relevant. Security
related to authenticated URLs are discussed in section 4 of
document
Many email clients store the plain text password for later use
logging into a POP server. Such clients MUST NOT use a
password in response to a POP URL without explicit permission
the user to supply that password to the specified host name
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RFC 2384 POP URL Scheme August 1998
10.
This document borrows heavily from Chris Newman's [IMAP-URL
specification, and has attempted to follow the advice in [URL
GUIDELINES].
11.
[ABNF] Crocker, D., and P. Overell, "Augmented BNF
Syntax Specifications: ABNF", RFC 2234,
1997.
[ACAP] Newman, C., and J. Myers, "ACAP --
Configuration Access Protocol", RFC 2244,
1997.
[BASIC-URL] Berners-Lee, T., Masinter, L., and M. McCahill
"Uniform Resource Locators (URL)", RFC 1738,
December 1994.
[IMAP-URL] Newman, C., "IMAP URL Scheme", RFC 2192,
1997.
[IMAP4] Crispin, M., "Internet Message Access Protocol -
Version 4rev1", RFC 2060, December 1996.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to
Requirement Levels", BCP 14, RFC 2119, March 1997.
[POP-AUTH] Myers, J., "POP3 AUTHentication command", RFC 1734,
December 1994.
[POP3] Myers, J., and M. Rose, "Post Office Protocol --
Version 3", STD 53, RFC 1939, May 1996.
[SASL] Myers, J., "Simple Authentication and Security
(SASL)", RFC 2222, October 1997.
[URL-GUIDELINES] Masinter, Alvestrand, Zigmond, "Guidelines for
URL Schemes", Work in Progress
[UTF8] Yergeau, F., "UTF-8, a transformation format of
10646", RFC 2279, January 1998.
Gellens Standards Track [Page 6]
RFC 2384 POP URL Scheme August 1998
12. Author's
Randall
QUALCOMM,
6455 Lusk Blvd
San Diego, CA 92121-2779
U.S.A
Phone: +1 619 651 5115
Fax: +1 619 651 5334
EMail: Randy@Qualcomm.
Gellens Standards Track [Page 7]
RFC 2384 POP URL Scheme August 1998
13. Full Copyright
Copyright (C) The Internet Society (1998). All Rights Reserved
This document and translations of it may be copied and furnished
others, and derivative works that comment on or otherwise explain
or assist in its implementation may be prepared, copied,
and distributed, in whole or in part, without restriction of
kind, provided that the above copyright notice and this paragraph
included on all such copies and derivative works. However,
document itself may not be modified in any way, such as by
the copyright notice or references to the Internet Society or
Internet organizations, except as needed for the purpose
developing Internet standards in which case the procedures
copyrights defined in the Internet Standards process must
followed, or as required to translate it into languages other
English
The limited permissions granted above are perpetual and will not
revoked by the Internet Society or its successors or assigns
This document and the information contained herein is provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
Gellens Standards Track [Page 8]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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