One of the difficult problems on the Internet is finding the electronic mail addresses of users. In practice, there are some indirect ways of finding these addresses such as the finger program in UNIX, but almost all of these methods require the user to know the exact host name of the destination. What is most desirable is an automated mechanism which provides the e-mail addresses of users if some minimal information about the destination site is known.

This thesis describes the design of such a directory service support system, based on the X.500 Series of CCITT Recommendation, for the elm electronic mail facility in the UNIX environment. The purpose of the system is to provide easy access to the electronic mail addresses of users, without requiring the direct use of the X.500 directory system. To facilitate the service, the user only needs to know the approximate name of the person and the location he/she works at. The query is done automatically and the returned e-mail address is used for the “To:” field in the header. In case of multiple hits, the sender has a few options: he can choose between the possible solutions offered by the system, ask for more information about a person or eliminate ambiguous references from the original request.

The system was designed and implemented on a Sun SparcStation. Tests were conducted to measure the response time of the system and the results are reported. Work is in progress to provide more functionality and a better user interface.


Computer Science


This report is substantially the M.S. thesis of the first author, completed July 1993.

Report Number


Document Type

Technical Report

Document Version

Final Version

File Type





© 1993 University of Missouri--Rolla, All rights reserved.

Publication Date

01 Jul 1993