X.500

X.500 is the set of ITU-T computer networking standards covering electronic directory services such as white pages, Knowbot and whois. X.500 was jointly developed with ISO as part of the Open Systems Interconnect suite of protocols, in order to support the requirements of X.400 electronic mail and name lookup.

The protocols defined by X.500 included Directory Access Protocol, Directory System Protocol, Directory Information Shadowing Protocol, and Directory Operational Bindings Management Protocol.

One of the X.500 series of specifications which has seen the widest use is not one of the directory protocols, however, but X.509, the specification of public-key certificates.

Compare: LDAP.

External links

• Understanding X.500 – The Directory (Copyright 1994, 1996 D W Chadwick.)

Article based on X.500 at FOLDOC, used with permission.