+\S{config-tcp-keepalives} \q{Enable TCP keepalives}
+
+\cfg{winhelp-topic}{connection.tcpkeepalive}
+
+\e{NOTE:} TCP keepalives should not be confused with the
+application-level keepalives described in \k{config-keepalive}. If in
+doubt, you probably want application-level keepalives; TCP keepalives
+are provided for completeness.
+
+The idea of TCP keepalives is similar to application-level keepalives,
+and the same caveats apply. The main differences are:
+
+\b TCP keepalives are available on \e{all} connection types, including
+Raw and Rlogin.
+
+\b The interval between TCP keepalives is usually much longer,
+typically two hours; this is set by the operating system, and cannot
+be configured within PuTTY.
+
+\b If the operating system does not receive a response to a keepalive,
+it may send out more in quick succession and if terminate the connection
+if no response is received.
+
+TCP keepalives may be useful for ensuring that half-open connections
+are terminated than for keeping a connection alive.
+
+TCP keepalives are disabled by default.
+