The Session Idle Limit (Server idle timer interval) is set using Citrix Policies and appears to be successfully applied to the XenApp Server. However, the session idle timeout does not apply at the given interval. It was noticed that the session idle time interval was set to 6 minutes, but did not apply until an hour later.

As the policy was applied to Remote Desktop Services it affects both ICA/RDP listening protocols. The use of Citrix IMA or Group policies to control the server idle timer interval is recommended.

Problem Cause

Checking the policies registry key reveals the MaxIdleSessionTimeout has been set correctly under ICA key but the time interval is not honored.
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\ICAPolicies
MaxIdleSessionTimeout 360000 (6 minutes)

After blocking the group policy inheritance on the XenApp OU, the ICA server idle timeout applied successfully. Further investigation into group policies applied to the server revealed that a Remote Desktop Services idle session limit was applied.

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services
MaxIdleTime 3600000 (1 hour)

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