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Do You Have The Time?
RetroGeek writes: "This ZDNet article talks about the perils of the PC clock. And (something I did not know) that Windows XP and Mac OS X both automatically get a time stamp from MicroSoft and Apple respectively. At any rate, my home firewall gets the time every hour from the NIST servers, then each of the machines on my LAN query the time server daemon on the firewall. That way all my home network machines have the same time. And latency on the LAN is next to zero. Now if I can only get my VCR connected. Anyone else running a time server?" So how do you get the time?
Ok, this is bad. A somewhat critical state of the OS is dependant on a blindly connected service. Please tell me the time server is authenticated fully and unbreakably. Hah.
Just wait for
1) MS to implement expirable licenses on all software
2) someone to break the authentication service
3) IP spoofing of the time server to a clock set 100 years in the future when everyones time based license has expired
The result is instant crippling of all MS licenses!
Comment removed based on user account deletion
Excuse me, but you are ignorant. The operating system is almost irrelevant here. Any fool can have a clock accurate to a second or so (or more to my point, a lot more accurate... But most people will not quibble about a second). More accuracy is hard. NTP. Even with a decent protocol you have latency. It matters not what your operating system is. It matters more where on the planet your system resides. This is a known physical latency. There are relativistic effects... But seriously, don't worry about them... You will not notice... Trust me!
Indeed.
/sbin/hwclock --systohc. Very useful, especially as a cron job on the local ntp server.
Please listen to this guy. Stratum 2 or higher is perfectly fine for a corporate network let alone a home network.
Please don't overload the stratum 1 servers, it really doesn't buy you anything.
As others have suggested, please set up one machine to run an ntp server e.g. xntpd, and sync off the remote ntp server and have other hosts sync off the local ntp server. This is desirable from your POV anyway. Why send NTP traffic across the internet if you don't really have to? That means more traffic (yeah, negligable) and higher and unpredictable latency to the ntp server. That latency matters: ntp tries to compensate for it but of course the lower and more constant the latency the better.
Also if you're running linux (and perhaps other *nixes), learn about
Cheers
Andy
"Yeah well there's a lot of stuff that should be, but isn't"
I've meet someone who uses GPS to find out how much his country (Sweeden) moves. He has a plot of most of Europes movments. The plots are on an sheet of paper in actual scale. Aparently Sweeden moves a few inches a year.