The number of milliseconds of inactivity a server needs to wait for additional incoming data, after it has finished writing the last response, before a socket will be destroyed.
This timeout value is combined with the server.keepAliveTimeoutBuffer option to determine the actual socket timeout, calculated as: socketTimeout = keepAliveTimeout + keepAliveTimeoutBuffer If the server receives new data before the keep-alive timeout has fired, it will reset the regular inactivity timeout, i.e., server.timeout.
A value of 0 will disable the keep-alive timeout behavior on incoming connections. A value of 0 makes the HTTP server behave similarly to Node.js versions prior to 8.0.0, which did not have a keep-alive timeout.
The socket timeout logic is set up on connection, so changing this value only affects new connections to the server, not any existing connections.