I have 30 identical Lenovo desktop systems running CentOS 5.1. On one of those systems the clock is running slow (5+ minutes from yesterday to this morning and another minute since this morning) despite the fact that NTP is running on all of them and they all have the exact same /etc/ntp.conf file (I compared the MD5 sums of that file on all the systems). Here is the output of "grep ntp /var/log messages" on the system with the problem since I restarted the NTP daemon earlier today: May 20 11:35:38 hepdsw03 ntpd[31791]: ntpd 4.2.2p1 at 1.1570-o Sat Nov 10 12:33:50 UTC 2007 (1) May 20 11:35:38 hepdsw03 ntpd[31792]: precision = 1.000 usec May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface wildcard, 0.0.0.0#123 Disabled May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface wildcard, ::#123 Disabled May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface lo, :: 1#123 Enabled May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface eth0, fe80::210:c6ff:feab:dd92#123 Enabled May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface lo, 127.0.0.1#123 Enabled May 20 11:35:38 hepdsw03 ntpd[31792]: Listening on interface eth0, 10.66.42.109#123 Enabled May 20 11:35:38 hepdsw03 ntpd[31792]: kernel time sync status 0040 May 20 11:35:38 hepdsw03 ntpd[31792]: frequency initialized 0.000 PPM from /var/lib/ntp/drift May 20 11:38:55 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), stratum 10 May 20 11:38:55 hepdsw03 ntpd[31792]: kernel time sync disabled 0001 May 20 11:39:59 hepdsw03 ntpd[31792]: synchronized to 10.101.32.104, stratum 3 May 20 11:40:58 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), stratum 10 May 20 11:42:09 hepdsw03 ntpd[31792]: synchronized to 10.101.32.104, stratum 3 May 20 11:47:26 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), stratum 10 May 20 11:49:31 hepdsw03 ntpd[31792]: synchronized to 10.101.32.104, stratum 3 May 20 11:52:48 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), stratum 10 May 20 11:54:54 hepdsw03 ntpd[31792]: synchronized to 10.101.32.104, stratum 3 May 20 12:01:26 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), stratum 10 Any idea what could be causing this? For now I have disabled the NTP daemon and am running ntpdate once an hour. What complicates the matter is that we are using Kerberos for authentication, and after a day or so the user can not log into his system anymore because of the time skew. Alfred