NAC: End Systems disappear periodically from NAC / Access Control Appliance
End Systems are periodically removed from NAC End Systems are periodically removed from Control
Access Control Appiance
Extreme Management Center
If an End System was not active for the amount (or greater) of days that is defined within the 'Age 'End-Systems older than' variable, the end system is removed from the NAC.
The default value is 90 days. For example, if an end system is no active for >90 days, using this default setting and the default 'Remote Associated Registration Data' is checked, the End system is removed completely from the NAC. . Entering 0 does not stop aging end systems. It will just purge it at the next Date Persistence Check time.
In the NAC Manager, open the Tools-->Options Menu and location the Age Systems older than variable. The default is 90 days:
In Extreme Management Center, this is found under Administration->Options->Access Control->Data Persistence->Daily Persistence.