The Basics: An Introduction to Directory Services, LDAP, and X.500

A section of An LDAP Roadmap & FAQ: A tutorial aid to navigating various LDAP and X.500 resources on the Internet, v2.0a

These are basic introductory documents to directory services in general, and X.500 and LDAP in particular. I've arranged them to be read nominally in this order -- but of course that's entirely up to you. There's a fair amount of overlap in these overview docs, by the way....

• Hodges97    Introduction to Directories and LDAP, Jeff Hodges, June 1997.


The Introduction sections of Hodges97 are relevant for those just beginning (duh!)...

• Introduction to Directories
• Introduction to LDAP

• What is a directory service? and What is LDAP?, from The SLAPD and SLURPD Administrator's Guide, University of Michigan, Release 3.3, April 30, 1996


Sections 1.1 and 1.2 of the above gives a succinct definition of directory services, and then gives an introductory definition of LDAP based upon it.

• Howes95    The Lightweight Directory Access Protocol: X.500 Lite, Timothy A. Howes, July 27, 1995, CITI Technical Report 95-8


Howes95  gives a good overview of the X.500 model, and then describes the LDAP model and rationale in detail.

• Chadwick96    Understanding X.500 - The Directory, David Chadwick, University of Salvord, UK. International Thomson Computer Press edition 1996 ISBN 185 0332 813.


This book is an excellent text on X.500. Next best thing is to read the X.500 documents themselves (see this page for pointers to them).

• Vendor-specific Directory information resources


The papers below have salient introductory information about directory services, though they are quite vendor-specific...

• An Internet Approach to Directories, Netscape, 1997.
• Novell Directory Service (NDS) White Paper, Novell, 1997.
• Exchange Directory Service (LDAP), Microsoft, 1997.

• The Webopaedia's LDAP page

The PC Webopaedia is a good starting point to learn about many aspects of Internet technologies and to find definitions of and further resources for technical terms. It is a product of Sandy Bay Software and is advertiser-supported.

• rfc1308    Executive Introduction to Directory Services Using the X.500 Protocol. C. Weider, J. Reynolds. March 1992. (Format: TXT=9392 bytes) (Status: INFORMATIONAL, FYI 13)


RFC1308 gives a good, concise overview of the X.500 model. Note that LDAP is based closely upon the X.500 model.

• rfc1309    Technical Overview of Directory Services Using the X.500 Protocol. C. Weider, J. Reynolds, S. Heker. March 1992. (Format: TXT=35694 bytes) (Status: INFORMATIONAL, FYI 14)


RFC1309 builds upon the one above to provide a more detailed technical introduction to how X.500-based directory services work.

• rfc1684    Introduction to White Pages Services based on X.500. P. Jurg. August 1994. (Format: TXT=22985 bytes) (Status: INFORMATIONAL)


RFC1684 provides an overview of both X.500 basics, plus how X.500-based Directory services globally work in a broad sense.