Network Working Group Tim Howes INTERNET-DRAFT Mark Smith University of Michigan 18 December, 1995 An LDAP URL Format 1. Status of this Memo This document is an Internet-Draft. Internet-Drafts are working docu- ments of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). 2. Abstract LDAP is the Lightweight Directory Access Protocol, defined in [1] and [2]. This document describes a format for an LDAP Uniform Resource Locator which will allow Internet clients to have direct access to the LDAP protocol. While LDAP currently is used only as a front end to the X.500 directory, the URL format described here is general enough to han- dle the case of stand-alone LDAP servers (i.e., LDAP servers not back- ended by X.500). Howes & Smith [Page 1] RFC DRAFT December 1995 3. URL Definition An LDAP URL begins with the protocol prefix "ldap" and is defined by the following grammar. ::= "ldap://" [ ] "/" [ "?" [ "?" "?" ] ] ::= [ ":" ] ::= a string as defined in RFC 1485 ::= NULL | ::= | [ "," ] ::= a string as defined in RFC 1777 ::= "base" | "one" | "sub" ::= a string as defined in RFC 1558 The ldap prefix indicates an entry or entries residing in the LDAP server running on the given at the given . The default port is TCP port 389. The is an LDAP Distinguished Name using the string format described in [1], with any URL-illegal charac- ters (e.g., spaces) escaped using the % method described in RFC 1738. The construct is used to indicate which attributes should be returned from the entry or entries. Individual attribute type names are as defined in RFC 1777. If the part is omitted, all attributes of the entry or entries should be returned. The construct is used to specify the scope of the search to per- form in the given LDAP server. The allowable scopes are "base" for a base object search, "one" for a one-level search, or "sub" for a subtree search. If is omitted, a scope of "base" is assumed. The is used to specify the search filter to apply to entries within the specified scope during the search. It has the format speci- fied in [4], with any URL-illegal characters escaped using the % method described in RFC 1738. If is omitted, a filter of "(objectClass=*)" is assumed. Note that if the entry resides in the X.500 namespace, it should be reachable from any LDAP server that is providing front-end access to the X.500 directory. If the part of the URL is missing, the URL Howes & Smith [Page 2] RFC DRAFT December 1995 can be resolved by contacting any X.500-back-ended LDAP server. 4. Examples The following are some example LDAP URLs using the format defined above. An LDAP URL referring to the University of Michigan entry, available from any X.500-capable LDAP server: ldap:///o=University%20of%20Michigan,c=US An LDAP URL referring to the University of Michigan entry in a particu- lar ldap server: ldap://ldap.itd.umich.edu/o=University%20of%20Michigan,c=US This URL corresponds to a base object search of the "o=University of Michigan, c=US" entry using a filter of (objectclass=*), requesting all attributes. An LDAP URL referring to only the postalAddress attribute of the Univer- sity of Michigan entry: ldap://ldap.itd.umich.edu/o=University%20of%20Michigan,c=US?postalAddress The corresponding LDAP search operation is the same as in the previous example, except that only the postalAddress attribute is requested. An LDAP URL referring to the set of entries found by querying any X.500-capable LDAP server and doing a subtree search of the University of Michigan for any entry with a common name of "Babs Jensen", retriev- ing all attributes: ldap:///o=University%20of%20Michigan,c=US??sub?(cn=Babs%20Jensen) An LDAP URL referring to all children of the c=GB entry: ldap://ldap.itd.umich.edu/c=GB?objectClass?one The objectClass attribute is requested to be returned along with the entries. 5. Security Considerations The LDAP URL format does not provide a way to specify credentials to use when resolving the URL. Therefore, it is expected that such requests will be unauthenticated. The security implications of resolving an LDAP URL are the same as those of resolving any LDAP query. See the RFC 1777 for more details. Howes & Smith [Page 3] RFC DRAFT December 1995 6. Prototype Implementation Availability There is a prototype implementation of the specification defined in this document available. It is an extension to the libwww client library, provided in both source and binary forms. Also included are binary ver- sions of the Mosaic WWW client for various platforms. See the following URL for more details: ftp://terminator.rs.itd.umich.edu/ldap/url/ 7. Bibliography [1] A String Representation of Distinguished Names. S. Kille, Request for Comment (RFC) 1779, March 1995. [2] Lightweight Directory Access Protocol. Wengyik Yeong, Tim Howes, Steve Kille, Request for Comment (RFC) 1777, March 1995. [3] The String Representation of Standard Attribute Syntaxes. T. Howes, S. Kille, W. Yeong, C.J. Robbins; Request for Comment (RFC) 1778, March 1995 [4] A String Representation of LDAP Search Filters. T. Howes; Request for Comment (RFC) 1558, December 1993 [5] Uniform Resource Locators (URL). T. Berners-Lee, L. Masinter, M. McCahill; Request for Comment (RFC) 1738, December 1994. 8. Acknowledgements This material is based upon work supported by the National Science Foun- dation under Grant No. NCR-9416667. 9. Author's Address Tim Howes University of Michigan ITD Research Systems 535 W William St. Ann Arbor, MI 48103-4943 USA +1 313 747-4454 tim@umich.edu Mark Smith University of Michigan ITD Research Systems 535 W William St. Howes & Smith [Page 4] RFC DRAFT December 1995 Ann Arbor, MI 48103-4943 USA +1 313 764-2277 mcs@umich.edu This Internet Draft expires June 18, 1996. Howes & Smith [Page 5]