A protocol for accessing information in a directory service based on the X.500 recommendations. The Directory Access Protocol (DAP) specifies how an X.500 Directory User Agent (DUA) communicates with a Directory System Agent (DSA) to issue a query. Using DAP, users can view, modify, delete, and search for information stored in the X.500 directory if they have suitable access permissions.
DAP is a complex protocol with a lot of overhead, which makes it generally unsuitable for implementations in a Microsoft Windows environment. A simpler version called Lightweight Directory Access Protocol (LDAP) is growing in popularity and can be used to access and update directory information in X.500 directories. LDAP is more suitable than DAP for implementation on the Internet and has mostly superseded DAP as an access protocol for X.500-based directories (which are now often called LDAP directories).