Represents a referral which is a set of alternative locations where an entry
can be found. Here's what
RFC 2251 has to say about it:
4.1.11. Referral
The referral error indicates that the contacted server does not hold
the target entry of the request. The referral field is present in an
LDAPResult if the LDAPResult.resultCode field value is referral, and
absent with all other result codes. It contains a reference to
another server (or set of servers) which may be accessed via LDAP or
other protocols. Referrals can be returned in response to any
operation request (except unbind and abandon which do not have
responses). At least one URL MUST be present in the Referral.
The referral is not returned for a singleLevel or wholeSubtree search
in which the search scope spans multiple naming contexts, and several
different servers would need to be contacted to complete the
operation. Instead, continuation references, described in section
4.5.3, are returned.
Referral ::= SEQUENCE OF LDAPURL -- one or more
LDAPURL ::= LDAPString -- limited to characters permitted in URLs
If the client wishes to progress the operation, it MUST follow the
referral by contacting any one of servers. All the URLs MUST be
equally capable of being used to progress the operation. (The
mechanisms for how this is achieved by multiple servers are outside
the scope of this document.)
URLs for servers implementing the LDAP protocol are written according
to <a href="http://www.faqs.org/rfcs/rfc2255.html">[9]</a>. If an alias
was dereferenced, the <dn> part of the URL MUST be present, with the new
target object name. If the <dn> part is present, the client MUST use this
name in its next request to progress the operation, and if it is not present
the client will use the same name as in the original request. Some servers
(e.g. participating in distributed indexing) may provide a different filter
in a referral for a search operation. If the filter part of the URL
is present in an LDAPURL, the client MUST use this filter in its next
request to progress this search, and if it is not present the client
MUST use the same filter as it used for that search. Other aspects
of the new request may be the same or different as the request which
generated the referral.
Note that UTF-8 characters appearing in a Dn or search filter may not
be legal for URLs (e.g. spaces) and MUST be escaped using the %
method in RFC 1738 <a href="http://www.faqs.org/rfcs/rfc1738.html">[7]</a>.
Other kinds of URLs may be returned, so long as the operation could
be performed using that protocol.