Referrals

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Referrals provide a way for servers to refer clients to more directory servers. A referral specifies the URL of an alternate LDAP server. This alternate server handles any requests for objects that are not found within any of the subtrees of the current LDAP server.

Note:
  • In a proxy environment, the proxy server does not return referrals. Referral objects are returned as normal directory entries, such that a client does not chase referrals.
  • Referrals are not recommended in a proxy environment.
A default referral can be used to point to the following servers:
  • The immediate parent of this server (in a hierarchy)
  • A "more knowledgeable" server, such as the uppermost server in the hierarchy
  • A "more knowledgeable" server that possibly serves a disjoint portion of the namespace
With referrals, you can run the following tasks:
  • Distribute namespace information among multiple servers
  • Provide knowledge of where data is located within a set of interrelated servers
  • Route client requests to the appropriate server
Note: All supported servers and clients for IBM® Securitry Directory Server 6.0 and above versions are enabled to support IPv6 and IPv4 formats. See IPv6 support for information about these two formats.
Some of the advantages of using referrals are the ability to carry out the following tasks:
  • Distribute processing overhead, providing primitive load balancing
  • Distribute administration of data along organizational boundaries
  • Provide potential for widespread interconnection, beyond an organization's own boundaries
Note: On Linux™ operating systems, if a client hangs while chasing referrals, ensure that the environment variable LDAP_LOCK_REC is set in your system environment. No specific value is required. 
set LDAP_LOCK_REC=anyvalue