https://ntp.isc.org/bugs/show_bug.cgi?id=759

--- ntp-4.2.4p0/ntpd/ntp_proto.c.retcode	2006-12-28 13:03:32.000000000 +0100
+++ ntp-4.2.4p0/ntpd/ntp_proto.c	2007-05-22 15:20:07.000000000 +0200
@@ -303,7 +303,7 @@
 				if (peer_ntpdate == 0) {
 					msyslog(LOG_NOTICE,
 					    "no reply; clock not set");
-					exit (0);
+					exit (1);
 				}
 			}
 		}