Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!


Click here to return to the '10.5: Back to My Mac fails to start due to incorrect time' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
10.5: Back to My Mac fails to start due to incorrect time
Authored by: goatbar on Apr 27, '09 08:43:24AM

In order for NTP to work, it needs multiple time servers. Apple's initial ntp.conf file is not good. I recommend using the ntp pool. e.g. for folks in the United States:

cat /etc/ntp.conf
server 0.us.pool.ntp.org
server 1.us.pool.ntp.org
server 2.us.pool.ntp.org
server 3.us.pool.ntp.org
server 0.north-america.pool.ntp.org
server 1.north-america.pool.ntp.org
server 2.north-america.pool.ntp.org
server 127.127.1.0

You can then query how well ntp is doing like this:

ntpq -p -n
remote refid st t when poll reach delay offset jitter
==============================================================================
+216.184.20.83 66.220.9.122 2 u 34 128 377 153.490 68.502 241.051
x209.67.219.106 74.53.198.146 3 u 28 128 377 82.082 522.860 450.415
-174.133.44.162 132.163.4.103 2 u 31 128 377 77.303 498.074 433.132
+216.45.57.39 204.123.2.5 2 u 48 128 377 198.298 26.814 240.223
x74.208.145.168 128.59.59.177 3 u 52 128 377 76.065 511.502 421.497
*128.10.252.7 .GPS. 1 u 82 128 377 79.171 62.040 170.801
127.127.1.0 .LOCL. 5 l 6 64 377 0.000 0.000 0.001



[ Reply to This | # ]
10.5: Back to My Mac fails to start due to incorrect time
Authored by: mnewman on Apr 27, '09 04:21:59PM

goatbar, can you explain the "server 127.127.1.0" entry in your ntp.conf file?

---
http://www.mgnewman.com



[ Reply to This | # ]
10.5: Back to My Mac fails to start due to incorrect time
Authored by: j-beda on Apr 29, '09 06:47:39AM

Maybe that is his router's address? I think that many routers might have an NTP server running.



[ Reply to This | # ]
10.5: Back to My Mac fails to start due to incorrect time
Authored by: goatbar on May 08, '09 01:34:05PM

That would be so that if the network goes down, ntp will default back to using the computers internal clock.

-kurt



[ Reply to This | # ]
ntp pool info
Authored by: j-beda on Apr 29, '09 06:45:11AM
Great info, I had been just using ca.pool.ntp.org in the "date and time" control panel, but edited the /etc/ntp.conf file to include the 0123 servers for ca as well as the NA ones as well. Some details of the NTP pools are at:

http://www.pool.ntp.org/

They seem to be suggesting using at least three, selecting from the closest (in networking terms) pool to you.

When I updated my ntp.conf file, and tried "ntpq -p -n", I got no change from before the edit, so I used the "Date and Time" panel in "System Preferences" to uncheck the "use network time server" box, and then checked the box again - that seems to have restarted the NTP process and loaded the new ntp.conf file. There is probably a way of doing that from the command line of course, but the checkbox was easier to find.



[ Reply to This | # ]