Returns a positive LDAP link identifier on success, or false on error.
ldap_connect() establishes a connection to a LDAP server on a specified hostname and port. Both the arguments are optional. If no arguments are specified then the link identifier of the already opened link will be returned. If only hostname is specified, then the port defaults to 389.
If you are using OpenLDAP 2.x.x you can specify a URL instead of the hostname. To use LDAP with SSL, compile OpenLDAP 2.x.x with SSL support, configure PHP with SSL, and use ldaps://hostname/ as host parameter. The port parameter is not used when using URLs. URL and SSL support were added in 4.0.4.