Hi CentOS users We are running CentOS 4.5 with NTP 4.2.0. # cat /etc/ntp.conf restrict default ignore restrict dns1.xxx.xxx mask 255.255.255.0 nomodify notrap noquery restrict dns2.xxx.xxx mask 255.255.255.0 nomodify notrap noquery restrict 127.0.0.1 server dns1.xxx.xxx server dns2.xxx.xxx fudge 127.127.1.0 stratum 10 driftfile /etc/ntp/drift broadcastdelay 0.008 authenticate no The problem is that other hosts are able to synchronize the time from our servers. How to disable that? # lsof -i :123 COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME ntpd 4874 ntp 4u IPv4 35805 UDP *:ntp ntpd 4874 ntp 5u IPv6 35806 UDP *:ntp ntpd 4874 ntp 6u IPv4 35807 UDP localhost.localdomain:ntp ntpd 4874 ntp 7u IPv4 35808 UDP xxx:ntp ntpd 4874 ntp 8u IPv4 35809 UDP xxx:ntp ntpd 4874 ntp 9u IPv4 35810 UDP xxx:ntp ntpd 4874 ntp 10u IPv4 35811 UDP xxx:ntp NTP listens on every interface. cheers Simon -- XMPP: sjolle at swissjabber.org