!!! Overview 
The [{$pagename}] (commonly referred to as the ExRef Partition, contains information about objects that don't exist in a partition on the local server. 

The [Partition ID] of the [{$pagename}] is always 2. 

!! Example 
For instance, when a user logs in to the network, NDS looks up the user information by performing a name resolution process or "Tree Walking". The client software navigates the different partitions in the NDS tree until it finds the User object. If this process is repeated, however, every time the user logs in or the object is referenced, efficiency suffers. 

To avoid having to repeat the process, NDS builds an [NDS External References], essentially a pointer, to that object and stores it in the [{$pagename}] on the server from which the User object is making the request. The next time this user authenticates to the network, the [NDS External References] is used to quickly locate the object within NDS. The [NDS External References] are deleted if not used for an extended period of time. 

NOTE In addition to providing tree connectivity (that is, tree-walking ) and speeding up object authentication, exrefs are also used to keep track of nonlocal objects when an object is added as a file system or local object trustee, or when an object is added as a member of a group . 

!! NOT Synchronized 
Although the [{$pagename}] exists on every server, only servers with [NDS External References] populate it. Like the [System Partition], the [{$pagename}] is not synchronized with other servers. 



NOTE Objects stored in the ExRef partition are called [NDS External References] objects. 

!! More Information 
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