Directory Services


The ldap_simple_bind function authenticates a client to a server, using a plaintext password.

Caution   This function sends the name and password without encrypting them, and therefore someone eavesdropping on the network could read the password. Unless a TLS (SSL) encrypted session has been established, do not use this function. For more information about how to set up an encrypted session, see Initializing a Session.

ULONG ldap_simple_bind(
  LDAP* ld,
  PCHAR dn,
  PCHAR passwd


[in] The session handle.
[in] The name of the user to bind as. The bind operation uses the dn and passwd parameters to authenticate the user.
[in] The password of the user specified in the dn parameter.

Return Values

If the function succeeds, it returns the message ID of the operation initiated.

If the function fails, it returns -1 and sets the session error parameters in the LDAP data structure.


The ldap_simple_bind function initiates a simple asynchronous bind operation to authenticate a client to an LDAP server. Subsequent bind calls can be used to reauthenticate using the same connection.

To authenticate as a specific user, provide both the name of the entry (user) and the password for that entry. To authenticate an anonymous user, when no access permissions are required, pass NULL to both the dn and passwd parameters.

As an asynchronous function, ldap_simple_bind returns a message ID for the operation. Call ldap_result with the message ID to get the result of the operation. To cancel an asynchronous bind operation before it has completed, call ldap_abandon. Be aware that if an LDAP 2 server is contacted, do not attempt other operations over the connection until the bind call has successfully completed.

To return the results directly, use the synchronous routine ldap_simple_bind_s.

Multithreading: Bind calls are not safe because they apply to the connection as a whole. Use caution if threads share connections and try to thread binds with other operations.

Note  The Microsoft LDAP client uses a default timeout value of 120 seconds (2 minutes) for each bind-response roundtrip. This timeout value can be changed using the LDAP_OPT_TIMELIMIT session option. Other operations do not have a timeout unless specified using ldap_set_option.

When all of the operations on the session handle are completed, terminate the session by passing the LDAP session handle to the ldap_unbind function. Also, if the ldap_simple_bind call fails, the session handle should be freed with a call to ldap_unbind when no longer required for error recovery.


Client: Included in Windows XP and Windows 2000 Professional.
Server: Included in Windows Server 2003 and Windows 2000 Server.
Redistributable: Requires Active Directory Client Extension on Windows NT 4.0 SP6a and Windows 95/98/Me.
Unicode: Implemented as Unicode and ANSI versions on all platforms.
Header: Declared in Winldap.h.
Library: Use Wldap32.lib.

See Also

Functions, ldap_abandon, ldap_bind, ldap_bind_s, ldap_result, ldap_simple_bind_s, ldap_unbind, Establishing an LDAP Session