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I'm on process to migrate ntp server to another server. I already setup the ntp server on the new PC, reconfigure clients for the new server, but want to know nobody refers the older ntp server before shutting down the older ntp server. But as long as seeing the log files, there is no log about which client accessed the server, besides the log how the ntp-server synced with the public ntp-server.

How can I make sure who is referring the ntp server? Platform is x86 Debian sarge.


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up vote 2 down vote accepted

You can put a filter in you iptables (in ACCEPT) for port 123, with a log. All the connections will be logged to your kern.log file. Your will have all the IPs. I don't see how solve your problem with ntpdc.

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Works great! Did "iptables -A INPUT -p udp --destination-port 123 -j LOG" and it logs all traffic to /var/log/kern.log. Thanks! – Jose May 27 '10 at 16:42

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