Information
The registry value entry KeepAliveTime was added to the template file in the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\ registry key. The entry appears as MSS: (KeepAliveTime) How often keep-alive packets are sent in milliseconds (300,000 is recommended) in the SCE. This value controls how often TCP attempts to verify that an idle connection is still intact by sending a keep-alive packet. If the remote computer is still reachable, it acknowledges the keep-alive packet. An attacker who is able to connect to network applications could establish numerous connections to cause a denial of service (DoS) condition.
Solution
To implement the recommended configuration state, set the following Group Policy setting to 300000.
Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\MSS- (KeepAliveTime) How often keep-alive packets are sent in milliseconds
Impact- Keep-alive packets are not sent by default by Windows. However, some applications may configure the TCP stack flag that requests keep-alive packets. For such configurations, you can lower this value from the default setting of two hours to five minutes to disconnect inactive sessions more quickly.