Patch taken from Debian: http://bugs.debian.org/249216
------------------------------------------------------------------------
--- ntp-4.2.0/ntpdate/ntpdate.c~ipv6only-workaround
+++ ntp-4.2.0/ntpdate/ntpdate.c
@@ -1698,8 +1698,6 @@
            if (res->ai_family == AF_INET6)
                 if (setsockopt(fd[nbsock], IPPROTO_IPV6, IPV6_V6ONLY, (void*) &optval, sizeof(optval)) < 0) {
    		           netsyslog(LOG_ERR, "setsockopt() IPV6_V6ONLY failed: %m");
-   		           exit(1);
-		           /*NOTREACHED*/
     	        }
 #endif