On Mon, 21 Mar 2005 08:40:01 -0500, Paul A. Houle <ph18@xxxxxxxxxxx> wrote: > Well, I've always been a little worried about NTP. The US military runs > well-publicized and well-used NTP servers, and they wouldn't be doing > what we pay them to do if they weren't ready to slip somebody a bad packet > when duty calls. > You shouldn't be using the usno.navy.mil NTP servers since they are overloaded. Redhat provides a time server, clock.redhat.com, which gets its time from CDMA which gets it from GPS. Most of the public NTP servers in pool.ntp.org get their time from GPS or CDMA. Some may even have their own atomic clocks. Also, any one organization would have a hard time sending time to change your clock. ntpd has some sophisticated ways to find bad clocks and ignore them. This is a good reason to stick with ntpd instead of OpenNTPD. NTP isn't authenticated so there are attacks, like blocking all other sources and sending bad packets. But that is much likely to come from hackers, not the Naval Observatory. If you are concerned about security, buy your own GPS receiver. If you are really paranoid, buy your own atomic clock. - Ian
