U

unbind operation

The LDAP unbind operation is used to indicate that the client wants to disconnect from the server.

Note that the unbind operation cannot be used to destroy an authentication session while leaving the underlying connection established. If the client does not close the connection after sending an unbind request, then the server will. If there is a need to revert a connection to an unauthenticated state, then an anonymous bind operation should be performed.

The LDAP unbind request protocol op is defined as follows:

UnbindRequest ::= [APPLICATION 2] NULL

An unbind request does not contain any elements, and the server will not send a response to an unbind request.

unindexed search

An unindexed search is one that cannot be processed using the set of index defined in the server. It will necessitate iterating through most or all of the entries in the database.

Unindexed searches can be expensive for the server to process, users will only be allowed to perform unindexed searches if they have the unindexed-search privilege.

For more information, see Indexing Directory Data in Oracle Fusion Middleware Administration Guide for Oracle Unified Directory.

UNIX crypt algorithm

The UNIX crypt algorithm is a standard mechanism for encoding user passwords using a DES-based encryption scheme that ultimately results in a one-way message digest. It is called the “UNIX crypt” algorithm because it has historically been used as the default mechanism for encoding passwords in UNIX-based systems.

Note that the UNIX crypt algorithm is considered weak because it is based on a 56-bit encryption algorithm and uses only a 12-bit salt. Therefore, it should only be used in cases where clients expect to be able to retrieve the password from the server and compare its value against what the user supplied instead of attempting to verify it using an bind operation.

unsolicited notification

An unsolicited notification is a type of extended operation message that is special in that the server generates this kind of message without any corresponding request from the client. It may be used to notify the client of some important information.

The directory server currently supports a single unsolicited notification: the notice of disconnection unsolicited notification, which can be used to inform the client that the server is closing the connection.

URL

See LDAP URL.

user attribute

A user attribute is an attribute type with an attribute usage of userApplications. User attributes are used for actually storing information in the directory, as opposed to operational attribute which are used for storing state information used for internal server processing.

Whenever a search operation does not request any specific attributes to be returned, then all user attributes in matching entries will be returned. An explicit value of * (the asterisk) may also be included to explicitly include all user attributes.