This directive determines the maximum time that the server holds open an HTTP Keep-Alive connection or a persistent connection between the client and the server. The Keep-Alive feature for earlier versions of the server allows the client/server connection to stay open while the server processes the client request. The default connection is a persistent connection that remains open until the server closes it or the connection has been open for longer than the time allowed by KeepAliveTimeout.
The timeout countdown starts when the connection is handed over to the keep-alive subsystem. If there is no activity on the connection when the timeout expires, the connection is closed.
The default value is 30 seconds. The maximum value is 300 seconds (5 minutes).