resource ldap_connect ([ string $hostname = NULL [, int $port = 389 ]] )
Establishes a connection to a LDAP server on a specified hostname and port.
Returns a positive LDAP link identifier on success, or FALSE on error. When OpenLDAP 2.x.x is used, ldap_connect() will always return a resource as it does not actually connect but just initializes the connecting parameters. The actual connect happens with the next calls to ldap_* funcs, usually with ldap_bind(). If no arguments are specified then the link identifier of the already opened link will be returned.