Folks, I just poked around and discovered something interesting that affects Windows clients, both XP and Vista.
Microsoft has broken the NTP specification in that the client sends a request in symmetric active mode instead of client mode. According to the NTP spec, both ancient and modern, this causes the server to launch a symmetric passive association, which would be a serious security vulnerability. The NTPv4 servers, including those at USNO and NIST, have specific means to protect against this vulnerability, so as you might have noticed, synchronizing XP or Vista clients to those servers fails. However, I jimmied the code so that, while it will not launch an association if denied, it will reply in symmetric passive mode. In other words, the server behaves in the same way as with an ordinary client/server mode. With this change, now in the development branch, Windows XP and Vista now work correctly. I'm not happy about this. I thought Microsoft had fixed this long ago in a service pack. Now at least folks with 400 PCs don't all have to light up Windows NTP. Dave _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions