An alias is a special type of entry that references another entry in the server, much like a symbolic link in a UNIX file system. It should include the alias object class and the aliasedObjectName attribute with a value equal to the DN of the entry that it references.
Aliases are primarily used for search operations. In particular, the search request includes an element that specifies the dereference policy that should be used when aliases are encountered. The allowed dereference policy values include:
The server should never dereference alias entries.
The server should dereference any alias entries that it finds in the possible set of search result entries, but if the search base DN specifies an alias entry it will not be dereferenced.
The server should dereference the search base entry if it is an alias, but it will not dereference any aliases within the possible set of search result entries.
The server should dereference any aliases encountered, whether in the search base entry or in the possible set of search result entries.
Note that aliases are an optional part of the LDAPv3 protocol, and the directory server does not currently support them.