RFC 1491

A Survey of Advanced Usages of X.500

📅 published July 1993, from ietf

RFC 1491: A Survey of Advanced Usages of X.500 🦋

Part 1 of 3 🎀

Okay so bestie, here's the vibe check first. This is an FYI doc from July 1993 (FYI 21, if you're keeping score ✨). It was written by C. Weider of Merit Network, Inc. and R. Wright of Lawrence Berkeley Laboratory. It doesn't obsolete anything and doesn't update anything either, so no drama here 💅

Status of This Memo ✨

Quick legal-ish tea: this memo is informational only 💖 It does not specify an Internet standard, and distribution of it is unlimited 🌸

Abstract 🦋

Okay so this doc is the result of a survey where people were asked to spill about their advanced usages of X.500 🫶 The whole point is to show how different organizations are using X.500 in ways that go way past the "White Pages" service that everyone thinks of first. It's a product of the Integrated Directory Services Working Group, which lives in the Application and User Services Areas of the IETF 👑

1. Introduction 🌈

So here's the thing, as X.500 spreads across the Internet, organizations keep finding uses for it that are way beyond the "white pages" paradigm, which is how most people were introduced to it in the first place 😭 To document all these new uses and to hype up the wider use of X.500, we sent out a survey to collect "advanced usages" of X.500. Iconic behavior, honestly 🔥

1.1 The survey 📝

The survey is included here for two reasons:

completeness, and
we'd like to encourage anyone who reads this document to send us their advanced usage for inclusion in the next revision.

If you want to fill it out, send it to the working group list: IDS@merit.edu 💌

_____________________________________________________________________

Application Name:

Author(s):

Company or Institution:

e-mail address for more information:

If this is a product for public distribution, please give us the
  Type: FREE, COMMERCIAL PRODUCT, or PROTOTYPE/RESEARCH
  FREE               - Anyone may obtain this product at zero cost.
  COMMERCIAL PRODUCT - One may purchase this product.
  PROTOTYPE/RESEARCH - This product is not yet available, only a
                       prototype.

If FREE, please give us:
  * FTP and/or FTAM address (if available via FTP and/or FTAM):

If COMMERCIAL, please give us:
  * Directions to obtain product:

Availability: (When will product be available?)

List of platforms product runs on:
[The platform list can be general - e.g. UNIX]

Short Description (< 100 words):

Full Description (< 1 page):

                Fig. 1: Advanced Usages Survey Template

______________________________________________________________________

This survey went out to the following mailing lists: osi-ds@cs.ucl.ac.uk, disi@merit.edu (now ids@merit.edu), and dssig@ics.uci.edu 📬

1.2 Disclaimer ⚠️

Okay real talk, the descriptions of the advanced usages were written by the implementors, NOT by the members of IDS 🙈 IDS did work with the description authors to make them readable, but no guarantees can be made about how valid the descriptions are. Caveat emptor, bestie 💀

2. The Survey Responses 💜

2.1 Index to Responses 🗂️

Application                                                   Page

2.2.1  Global Time-table Information Service ................    3
2.2.2  Pre-Message Security Protocol         ................    4
2.2.3  Electronic Data Interchange           ................    5
2.2.4  Network Topology Information          ................    7
2.2.4.1  Shared Whois Information Project    ................    7
2.2.4.2  EARN's Network Directory            ................    8
2.2.5  Soft Pages                            ................    9
2.2.6  X-Tel                                 ................   10
2.2.7  Xerox Clearinghouse                   ................   12
2.2.8  X.500 Sendmail                        ................   13
2.2.9  Transparent ODA Conversion            ................   14
2.2.10 X.500 and the whois protocol          ................   16
2.2.11 X.400 table handling                  ................   17

2.2 Survey Responses 🌸

2.2.1 Global Time-table Information Service 🚆

Application Name: Global Time-table Information Service based on X.500

Date Received: 7/1/1992

Date Last Validated: 7/1/1992

Author(s): Jens Hofmann and Cuno Lanz 🫶

Company or Institution: Laboratory of Computer Engineering and Networks, Swiss Federal Institute of Technology (ETH Zurich), Switzerland 🇨🇭

e-mail address for more information: c=CH; a=ARCOM; p=SWITCH; o=ETHZ; ou=TIK; s=Lanz (lanz@tik.ethz.ch)

Type: experimental prototype; not public

FTP address: <none>

Short Description: This app is all about bringing together the time-table info from public transport providers of every scope (local, regional, national or international) into one homogeneous, unified user interface. X.500 stores the info in an autonomous and extensible way ✨

Full Description: Okay so most public transport providers offer some kind of time-table service, like a printed directory, a help desk, phone support or PC software. Unfortunately these have some drawbacks:

no automatic update of data (information accuracy)
no global availability (place independency)
no permanent availability (time independency)
no inter-provider service (service integration).

X.500 can help fix all of that 💖 Providers store their time-table info in a standardized format on locally managed DSAs. Then there's a special purpose DUA that (1) asks the user for the input parameters (date, time, source and destination station), (2) searches for the relevant paths by querying the involved DSAs, and (3) displays the resulting time-table to the user.

In a diploma thesis, a student is developing a new data model that makes it easy to select source and destination stations and quickly explore the time-table info 🧚 He's building a prototype on top of an existing DUA interface (based on HyperCard and running on Apple Macintosh), which connects to the world-wide X.500 pilot service over the DIXIE protocol. To test the prototype, the time-table info of the Swiss national public transport company and of most of the regional providers around the city of Zurich is included under the branch c=CH;o=ETH Zurich 🍓

2.2.2 Pre-Message Security Protocol 🔐

Application Name: Defense Message System Directory

Date Recieved: 7/1/1992

Date Last Validated: 7/1/1992

Author: Bob Cooney

Company or Institution: The Naval Computer and Telecommunications Station, Washington and The Defense Information System Agency

E-mail address for more information: cooney@wnyose.nctsw.navy.mil

Type: experimental prototype, not public

FTP address: <none>

Short Description: The U.S. Navy is building a directory based on X.500 to support the distribution of Pre-Message Security Protocol security keys 🔑

Long Description: So the U.S. Navy was asked to build a directory service that supports distributing Pre-Message Security Protocol security keys. The Pre-Message Security Protocol gives SMTP/X.400 security services for unclassified but sensitive mail on the Defense Data Network 💅

The directory will be based on QUIPU. Proof of concept is expected by October 1992, with initial operational capacity by October 1993 ⭐

2.2.3 Electronic Data Interchange 🛒

Application Name: An X.500 User Agent for Electronic Data Interchange

Date Received: 7/10/1992

Date Last Validated: 7/10/1992

Author: Neil Weldon

Company or Institution: Networks Group, Computer Science Dept., Trinity College Dublin, Ireland

e-mail address for more information: omahony@cs.tcd.ie and nmweldon@vax1.tcd.ie

Type: Research product and not for public distribution

FTP address: <none>

Short Description: The Directory helps solve the 'first order' problem that comes with Electronic Data Interchange (EDI). EDI is the transfer of trade documents between application processes in a processable form. The 'first order' problem is about the agreements two organizations need to make about capabilities and preferences before they can use EDI 🧠

To solve it, they defined object types that store product catalogues inside the Directory, plus info about the EDI readiness of trading partners: addresses, preferences and EDI capabilities 🎀

Full Description: Okay so Electronic Data Interchange (EDI) is how organizations swap trade-related documents between application processes, in a format that can be processed electronically 🤖

Before using EDI, an organization has to set a series of goals and objectives: what kinds of documents they want to send (invoices, purchase orders etc.) and what their communication requirements are. Each of these steps is time consuming and tedious, and it's usually done together with trading partners, because the agreements about EDI capabilities and preferences have to be made with them 😩

To solve this 'first order' problem (the need to reach agreements with other organizations before trading via EDI can happen), they defined object types that store product catalogues within the Directory. The Directory can also convey EDI readiness info about trading partners: addresses, preferences and EDI capabilities 💜

Using an experimental User Agent based on Pod, which was developed at Brunel in the UK, trade documents can be built up by picking products from the stored catalogues. Then those documents get encoded as an EDI Interchange after the Directory has been queried about addresses, etc. 🛍️

The current object types are very basic and can only convey the minimal amount of info needed. They're now being extended into a full product class hierarchy, based on the info that can be sent within an EDI trade document using the EDI standard document syntax EDIFACT 🌈

By using the Directory as a repository for product info to aid EDI, the catalogues become available worldwide. They can be replicated at various nodes, and updating and propagating changes to slave copies becomes trivial. Main character energy 👑✨

2.2.4 Network Topology Information 🗺️

There are two projects in this area: Merit Network's Shared Whois Information Project, and EARN's Network Directory 🦋

2.2.4.1 Shared Whois Information Project 🌸

okay bestie, this one is giving database drama 💅 here's the metadata, copied exactly:

Application Name: Shared Whois Project
Date Received: 6/1/1993
Date Last Validated: 6/1/1993
Author(s): Sheri Repucci
Company or Institution: Merit Network, Inc.
e-mail address for more information: swip@merit.edu
Availability: June 1993
Type:
  experimental prototype, not public
List of platforms product runs on: UNIX

Short Description 🔥 The Shared Whois Project merges network data from different organizations, mainly so it can find and fix conflicting network info between the databases. The longterm goal is to stop keeping similar or duplicate network info in a bunch of separate databases and move to an X.500 distributed database model. To get there, they're loading NSFNET network info into X.500 so they can join a distributed database trial.

Full Description ✨ The Shared Whois Project is a collection of programs and shell scripts that together merge the network data each participating organization holds. Right now that's Merit, the RIPE-NCC, and the InterNIC. The main point of merging this huge pile of data is to find and resolve conflicting info between the databases. The plan is to merge bi-weekly, so they can quickly reach a stable set of commonly held network info and keep it that way.

all three participants share a common set of information, but each org also holds extra info that's unique to what it does. The merged result keeps only one entry per network and doesn't try to blend the variations together. Instead, each entry lists every database that had info for that network, plus every database that conflicts with the entry in the final set. 🫶

The longterm goal is the same: move from storing duplicate network info everywhere to an X.500 distributed database model. Merit is working on loading NSFNET network info into X.500 so it can join a trial with the InterNIC and others on the way to a globally distributed database model. 🌈

2.2.4.2 EARN's Network Directory 🦋

Application Name: Ditnet/EARN Network Directory
Date Received: 7/7/1992
Date Last Verified: 7/7/1992
Author(s):
  Peter Sylvester
Company or Institution:
  Inria Rocquencourt - France
e-mail address for more information:
  peter.sylvester@inria.fr
Type: FREE (data owned by EARN/Bitnet)

Short Description 💖 The EARN/Bitnet network database has descriptions of all participating members, network nodes, administrators, and topology info. It's commonly known as BITEARN NODES, and it's being made available through x.500.

Full Description 🧚 The full rundown of what's in the EARN/Bitnet database lives in an internal EARN document. You can grab it as the file BITEARN NODES from any NETSERV in EARN/Bitnet. The file's contents get mapped into an X.500 subtree with descriptions of network nodes, administrative personnel, and topology info. 💅

The first version of the directory subtree will use a simple textual mapping to a flat directory tree, using private attributes. very basic, but it's a start 🌸

2.2.5 Soft Pages 🍓

Application Name: Soft Pages
Date Received: 9/25/1992
Date Last Validated: 9/25/1992
Author(s):
  Thomas Johannsen
  Glenn Mansfield
Company or Institution:
  AIC Systems Laboratory,
  Tohoku University Sendai
e-mail address for more information:
  spp-support@aic.co.jp
Type:
  Intended for public distribution, not yet public
FTP address: <none>

Short Description 🔍 Soft Pages is a file name look-up service for anonymous FTP servers. It gives you ls -lR info and the FTP server address, and it picks the nearest FTP site (from your site) that holds the file you want. 🧭

Full Description 💜 Electronic archives for documents, programs and the like keep growing in number and size, so finding and grabbing one specific file gets more complicated every day. Bandwidth on the Internet is still limited, too. People should be encouraged and supported to do local FTP sessions whenever they can, instead of pulling everything from the other side of the world. 🌍

The Soft Pages Project mixes an Archie-like file look-up service with network configuration knowledge. A dedicated User Agent suggests how to retrieve a document in a way that's optimized for network traffic. ✨

The Directory info from Soft Pages has two parts: a file information part and a network configuration part.

The file information part describes objects and attributes for file servers and their contents. For each file server, the names and attributes of its files are stored and updated periodically. That gives global access to Archie-like info for every registered file server, and it also means a document's description can be stored along with its file name. So searching isn't limited to file name matches; it can run on keywords too. 🔥
The network configuration part holds info on networks (subnetworks), nodes, and lines in the Internet. IP numbers can also be mapped to network and node objects. To evaluate file server sites, Internet connections (site to site) get a cost index, and then alternatives are compared by that index. The cost index is a calculated parameter that represents properties of a connection, like speed, average traffic, charges, and so on. The values for those properties are stored as attributes on line objects. 👑

If a document is stored at two or more sites, the site with the lowest cost index gets chosen for retrieval. That one is naturally the "nearest" in network terms. A Soft Pages User Agent basically talks to the Directory to find a pointer to the "best" copy of the file a user wants. 🎀

2.2.6 X-Tel 🌈

Application Name: X-Tel's advanced applications
Date received: 7/1/1992
Date last verified: 7/1/1992
Author(s):
  Colin Robbins
  Julian Onions
  Graeme Lunt
Company or Institution: X-Tel Services Ltd.
e-mail address for more information:
  x500@xtel.co.uk
Type:
  Commercial Products / Ideas

Short Description 🦋 X-Tel's list of ideas, one by one:

Product Information 💅 Products with DUA facilities built in have a "latest info" button or some other request method. When you press it, a well known node below the X-Tel part of the tree gets read. The attributes describe the latest software version and new features. If you want the new version, a second read grabs the info needed for a template order form.
BUG Status 🐛 Same idea, but it fetches details of known bugs in the version of the software you're running. (If only there were a way to put fixes in and auto-update the software itself! 😭)
X-Terms 🫶 It's a conferencing product that lets X users "talk" and share windows. The tricky part is figuring out which X Terminal device a particular user is on. One fix: update a user's directory entry during login to say which X display they logged into. The conference can then query the directory and open windows on the right device. The directory also stores details of current conferences, so new delegates can join easily. 🎀
Organisation browsing 👑 The directory stores a rich set of attributes about people and their roles. A special purpose DUA uses that to show who manages who, who is secretary for who, and so on. It's especially useful combined with the search ACL mechanism defined in OSI-DS 21, since different views can be given to different categories of users. 🔥
MHS use of directory 📬 The directory stores MHS routing info, as described in the MHS DS working group documents.
Mail Lists 💌 Details of mailing lists live in the directory. With careful use of access control, users can subscribe and unsubscribe themselves to and from a list. 🌸
Restaurants 🍕 Details of restaurants in the Nottingham area are stored in the directory!
Adventure game 🧚 They plan to use the directory as a rendezvous for a multi-user adventure game. Each "room" will be a different entry, and modify operations will be used to pick up and put down objects! 🗝️

The next two are "advanced" features of their DUA, and they may not be considered relevant to this document! 🙈

Templates 🍓 The directory stores template entries, and the DUA uses a template when adding new users. Very useful, since a number of default attributes can be set in advance.
Editors ✨ Special purpose editors for a number of complex attribute syntaxes are built into their DUAs. That includes QUIPU ACLs and X.400 OR Addresses. 💜

2.2.7 Xerox Clearinghouse 💅

Application Name: Clearinghouse Interface
Date Received: 7/1/1992
Date Last Validated: 7/1/1992
Author(s): Margaret Avino
Company or Institution: Xerox Corporation
e-mail address for more information: mavin.cin_ops@xerox.com
Type: Early Design/Implementation stages
Short Description: X.500 DSA interface to XNS (Xerox Network Services) Clearinghouse directory to provide access to Xerox Corporation's Clearinghouse via X.500 DUAs.

Okay so Xerox runs the XNS network protocol suite 🖥️✨ to provide Mail, Filing, Directory, Authentication, etc. network services for the installed base of 45,000+ Xerox workstations. The Directory is built on the XNS Clearinghouse protocol, which is kinda like X.500 because it holds objects that have properties (attributes) and it's a fully distributed, replicatable directory 🌈. The searching in the Clearinghouse protocol isn't as robust as the X.500 search operation, though, and the physical structure of the original database isn't great for complex searches the way it could be in a relational database 🥺.

The first piece of this project is moving the data into an Oracle relational database and making a new Clearinghouse server 🎀. That server reads from the Oracle database and is a full member of the Clearinghouse, so it sends and receives updates to and from other servers using the XNS Clearinghouse protocol. Iconic. This unlocks powerful SQL queries on the data, which gives us some seriously desired features, like: list all of the Distribution Lists of which this name is a member 💖.

To build on the new database, the team is probing the implementation of an X.500 DSA interface to the Oracle Clearinghouse Directory 🔍. This would let X.500 DUAs access the data and use the powerful search operations 🦋. It will need one or more new object classes, several new attributes, and some careful thought about the appropriate schema 🧚.

2.2.8 X.500 Sendmail 📬

Application Name: X.500 Sendmail
Date Received: 9/25/1992
Date Last Verified: 9/25/1992
Author(s): Tim Howes
Company or Institution: University of Michigan
e-mail address for more information: x500@umich.edu
Type: FREE
FTP address: terminator.cc.umich.edu
Directions to obtain product: get x500/sendmail-5.65.x500.tar.Z
Short Description: Modifications to sendmail-5.65 to do X.500 lookups.

The team at Michigan modified sendmail-5.65 so it does X.500 lookups 🫶, returning the value of a user's rfc822Mailbox attribute. 👑 If there are multiple matches, it sends a message listing the choices back to the sender. If the user has no email address in X.500, the sender gets a message with the user's postal and phone info instead 📞. Both exact and approximate matching are supported 💅.

2.2.9 Transparent ODA Conversion 📄✨

Application Name: Transparent ODA Conversion
Date Received: 7/16/1992
Date Last Verified: 7/16/1992
Author(s): MacFarland Hale (MITRE Open Systems Group)
Company or Institution: The MITRE Corporation
e-mail address for more information: machale@mitre.org
Type: Not Yet Available
Short Description: Plan to use X.500 in conjunction with X.400 and Open Document Architecture (ODA) to provide transparent translation of compound documents between a sender and one or more recipients.

Okay, bestie, this one is a whole vibe 🌸. In the future MITRE wants to combine X.500, X.400, and Open Document Architecture (ODA) to automate converting compound documents, so users don't need to know about ODA or even that a conversion is happening 🦋. That will need new and/or updated X.400 products.

Each user's preferred compound document format (like Microsoft Word, FrameMaker, etc.) gets stored in the X.500 directory 📚. Every X.400 Message Transfer Agent (MTA) host also has converters between each of those formats and the Open Document Interchange Format (ODIF) 🔧.

Here's the flow. A sender writes a document in their preferred compound document editor ✍️. Ideally the editor has a link (like a button or pull-down menu) to the X.400 User Agent (UA) 💖. The sender invokes the UA, either through that link or outside the editor, to send the document as an X.400 message to one or more recipients. Next, the document might need converting to ODIF, and that can happen in one of two ways 🙈.

The preferred way is that the X.400 MTA handles the ODIF conversion 👑. The UA has to somehow be told what format the original document is in. That can happen through the UA invocation from inside the editor, through a UA configuration file, by examining the filename extension, etc. 🗂️ Then the UA tags the document to show its original format, using one of the body parts: "Bilaterally Defined" (body part 14), "Nationally Defined" (body part 7), or "Externally Defined" (body part 15) 🏷️. The UA sends the message, and the MTA reads the tag to figure out the document's format 🕵️‍♀️.

For messages inside MITRE, the MTA looks up the recipient's preferred document format 🔍. If it's different from the sender's format, the MTA calls the right ODIF converter and sends the message. If the recipient's preferred format matches the format of the document being sent, no conversion happens 🎀. For messages going outside MITRE, the document is always converted to ODIF. The user can stop this by saying the enclosed document shouldn't be converted. In that case the UA just sends the document in binary form with no special tag 🙅‍♀️.

The other option is that the UA does the conversion 💅. Same deal as before: the UA must be told the document's original format. The UA can then call the appropriate local ODIF converter and send the message. But there are some disadvantages to this approach:

ODIF converters must be purchased for and maintained on many more hosts;
the document is always converted to ODIF (unless the UA accesses the directory, but...);
conversion overhead could be traumatic on a small PC. 😭

At each recipient host, the X.400 MTA catches the incoming message and recognizes the contents as ODIF 🥰. It then looks up the recipients' preferred compound document formats, calls the appropriate converters to translate the contents, and delivers the message to the recipients 📨. If the incoming message has one of the format tags described above, no conversion happens, since the document isn't in ODIF anymore 🌈.

Please note that MITRE is a not-for-profit organization ✨. They won't produce commercial products to support this scenario, but they're super eager to encourage and work with companies that want to do so 💜.

2.2.10 X.500 and the WHOIS protocol 📞

Application Name: Phone Book
Date Received: 7/15/1992
Date Last Verified: 7/15/1992
Author(s): Steven Schoch
Company or Institution: NASA Ames Research Center
e-mail address for more information: schoch@sheba.arc.nasa.gov
Type: FREE, see Steve
Short Description: On-line edition of our phone book, using X.500 for storage and retrieval.

Phone Book is a user application that talks over the Internet WHOIS protocol 🍓, and it's listed in the Internet Resources Guide as such. The latest version doesn't use a flat file anymore, though 🙌. It gets its info from a DUA that converts between information received via DAP and the format users expect back from Phone Book queries. Switching to X.500 means it can now show extra data, like E-mail addresses, that don't normally appear in the phone book 💖. The fields in a response are:

Name
Telephone Number
Mail Stop
Office Number
Organizational Affiliation (either a NASA organization code or a contractor name)
E-mail address

You can query on any of these fields, and the office is split into building and room components 🏢. A sample lookup looks like this:

trident:297-->phbook yee
Name                        Phone    M/S     Office    Organization
--------------------------- -------- ------- --------- ------------
Arnold M. Yee                 4-4315 258-6   N258/134  COMPSCICOR
Cindy Yee                            226-3   N226/105  CALSPAN
                                     cyee@ames.arc.nasa.gov
David H. Yee                  4-4106 213-8   N213/256  EEF
                                     david_yee@qmgate.arc.nasa.gov
Dr. Helen M C. Yee            4-4769 202A-1  N202A/216 RF
Harry Yee                     4-6557 213-2   N213/101F EES
Peter Edmond Yee              4-3812 233-18  N233/240  EDC
                                     yee@atlas.arc.nasa.gov
Robert Yee                    4-4122 T041-3  TA20/155  SFA
                                     robert_yee@qmgate.arc.nasa.gov

2.2.11 X.400 table handling 🗂️

Application Name: X.400 table handling
Date Received: 7/15/1992
Date Last Verified: 7/15/1992
Author(s): Julian Onions, Colin Robbins
Company or Institution: X-Tel Service Limited, Nottingham, England
e-mail address for more information: jpo@xtel.co.uk
Type: FREE, not yet available to the general public
Short Description: Implementation of the work of the IETF MHS-DS group. The goal is to put X.400 tables into X.500 in order to facilitate gateway and routing functions.

See the Internet drafts for MHS-DS 📝. NASA Ames Research Center is helping test and develop the next release of the PP message handling software 🚀. The latest update (alpha test) uses X.500 from X.400 for RFC 822<->X.400 gatewaying, and it also has hooks for X.400 intelligent routing ✨. Using X.500 to get rid of static tables will make it way easier to maintain the info needed for mail gatewaying and routing, and to keep that data current and well distributed 🌈.

3. Security Considerations 🔐

Okay, here's the tea 🫢. Security issues are not discussed in this memo. Not one word! So if you're implementing anything from this document, go in with your eyes open 👀.

4. Authors' Addresses 🎀

Chris Weider 2901 Hubbard, Pod G Ann Arbor, MI 48105

Phone: (313) 747-2730 EMail: clw@merit.edu

Russ Wright Lawrence Berkeley Laboratory 1 Cyclotron Road Berkeley, CA 94720

Phone: (415) 486-6965 EMail: wright@lbl.gov

📦 where this page comes from

ietf: rfc1491 1993-07
💖 girlified by claude-haiku-5-5 on 2026-10-17: a language model's rewrite of the original, under its terms