What are the consequences of disabling "Validation Period" on a Realm
configured for persistent session ?
Policy Server 12.8SP6 on RedHat 7;
According to documentation (1), when disabling the Validation Period,
the Web Agent will always try to validate the session from its cache
and it will only call Policy Server if the session is not available in
its cache.
On one hand, this should result in less calls to Policy Server and
Session Store. On the other hand, this might lead to the fact that the
Web Agent still validates the session, even if the session doesn't
exist anymore in the Session Store.
(1)
Realm Dialog Reference
Be aware of the following:
For persistent sessions, the Idle Timeout must be enabled and set
to a value higher than that specified for the Validation Period.
Validation Period
If enabled, determines the period that the Agent caches the result
of a session validation call to the Policy Server. Session
validation calls perform two functions: informing the Policy
Server that a user is still active and checking that the user
session is still valid. Session validation calls inform the Policy
Server that a user is active and confirm that the user session is
valid. If disabled, the agent always tries to validate the session
from its cache and only calls the Policy Server if the session is
not available in its cache.
To specify the validation period, enter values in the Hours,
Minutes, and Seconds fields. If you are configuring the system to
provide a Windows user security context, set this value high, for
example, 15-30 minutes.
Note: The Validation Period value must be greater than zero.
Important! The session validation period must be less than the
specified Idle Timeout value.
https://techdocs.broadcom.com/us/en/symantec-security-software/identity-security/siteminder/12-8/using/administrative-ui/realm-dialog-reference.html