3. Defaults for Fields of the LDAP URL

Some fields of the LDAP URL are optional, as described above. In the absence of any other specification, the following general defaults SHOULD be used when a field is absent. Note that other documents MAY specify different defaulting rules; for example, section 4.1.10 of [RFC4511] specifies a different rule for determining the correct DN to use when it is absent in an LDAP URL that is returned as a referral.

If no is given, the client must have some a priori knowledge of an appropriate LDAP server to contact. The default LDAP port is TCP port 389. If no is given, the default is the zero-length DN, "". If the part is omitted, all user attributes of the entry or entries should be requested (e.g., by setting the attributes field AttributeDescriptionList in the LDAP search request to a NULL list, or by using the special selector "*"). If is omitted, a of "base" is assumed. If is omitted, a filter of "(objectClass=*)" is assumed. If is omitted, no extensions are assumed.