16 Jan
2008
16 Jan
'08
5:38 p.m.
The zeros in the "reach" column indicate that the server has been unable to receive any packets from the upstream servers.
Is your server inside a firewall? If so, perhaps it is blocking NTP traffic. You need to have it allow UDP port 123 in both directions. You don't need port forwarding from outside to in, since all incoming packets will be replies to outgoing packets.
If it is not inside a firewall, perhaps you have iptables on the server itself blocking UDP port 123 traffic.
Fantastic, Tony. This is the information I needed. Our ISP does in fact block UDP packets and I suspect this is why the sync is failing.
One question though - how come I can use ntpdate servername to update them by hand? Shouldn't that be blocked as well?