I have five different servers listed in /etc/ntp.conf.  Recently, one of
them went off the air for a while.  However, although it was the only one
that was refusing NTP requests, while it was down I got log mesages
claiming that the *others* were, even though they weren't.

The host that was refusing connections was 66.92.64.2, but nothing was ever
logged about *that* host.  Instead, I got lots of these errors about the
*other* servers in my ntp.conf file, even though they were all working (as
confirmed by "dmpeers" in ntpdc:

Sep  4 00:24:26 jik ntpd[1043]: recvfrom(206.253.194.97) fd=6: Connection
refused
Sep  4 02:25:02 jik ntpd[1043]: recvfrom(216.231.41.22) fd=6: Connection
refused
Sep  4 02:29:19 jik ntpd[1043]: recvfrom(206.253.194.65) fd=6: Connection
refused
Sep  4 02:31:28 jik ntpd[1043]: recvfrom(18.72.0.144) fd=6: Connection
refused