Thanks for your kind answer. > Look into the "restrict" commands in ntp.conf to implement security > policies on NTP. You can find information on how it works on "man > ntp_acc". The default restrict config likes below. restrict default nomodify notrap noquery If I setup ntpd service as a client not server, above options are sufficient? I would like to deny any ntpd query packets except reply packets from others because of client. but it seems that other clients can query the date. Thanks in advance. _________________________________________________________________ 대딩들의 인맥관리! 윈도우 라이브 메신저로 해결하자! 채팅은 기본! 25GB 자료실은 덤! 대딩들의 아지트 윈메 클럽 http://im.msn.co.kr/Univ/ -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20090612/870ac036/attachment-0005.html>