L'heure sur mon Mac est en avance de 5 minutes sur l'heure réelle.

Si ni le pool ntp ni time.apple.com sont convenables ou accessibles à partir du réseau que vous utilisez, vous devrez peut-être régler votre horloge manuellement. Une fois que vous êtes à moins de 15 secondes de l'heure, essayez à nouveau l'option de ligne de commande et le réglage automatique.

De même, lorsque vous pouvez essayer un autre réseau ou un VPN vers un serveur situé dans une autre région géographique, cela peut vous aider à contourner les problèmes de réseau dans votre région.

D'après cette question sur Ask Ubuntu, il est fort probable que votre FAI bloque le port 123 dont ntp a besoin pour fonctionner.

• https://askubuntu.com/questions/429306/ntpdate-no-server-suitable-for-synchronization-found

Vous pouvez également obtenir une bonne date de serveur à partir de curl :

curl -I http://www.apple.com 2>/dev/null | grep ^Date:

Si vous vouliez analyser cela et définir la date, ce serait une solution facile pour une correction unique ou un alias que vous pourriez exécuter périodiquement à la ligne de commande. Pour déboguer correctement, voici la commande que j'utiliserais :

ntpdate -vd time.apple.com

Il vous montrera les paquets envoyés et reçus, puis une explication détaillée de la façon dont l'heure est modifiée comme ceci :

$ ntpdate -vd time.apple.com
21 Feb 13:12:49 ntpdate[17139]: ntpdate 4.2.6@1.2089-o Fri May 28 01:20:57 UTC 2010 (1)
Looking for host time.apple.com and service ntp
host found : jptyo5-ntp-002.aaplimg.com
transmit(17.253.68.253)
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transmit(17.253.68.253)
transmit(17.253.84.253)
receive(17.253.68.253)
transmit(17.253.68.253)
transmit(17.253.14.253)
receive(17.253.84.253)
transmit(17.253.84.253)
receive(17.253.14.253)
transmit(17.253.14.253)
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transmit(17.253.14.253)
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transmit(17.253.68.253)
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transmit(17.253.14.253)
receive(17.253.14.253)
transmit(17.253.14.253)
transmit(17.253.54.251)
receive(17.253.84.253)
transmit(17.253.84.253)
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transmit(17.253.68.253)
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transmit(17.253.54.251)
transmit(17.253.38.253)
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transmit(17.253.34.253)
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transmit(17.253.6.253)
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server 17.253.68.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.19341, dispersion 0.00044
transmitted 4, in filter 4
reference time:    da748aad.d730f54c  Sun, Feb 21 2016 13:12:45.840
originate timestamp: da748ab2.b8b599ea  Sun, Feb 21 2016 13:12:50.721
transmit timestamp:  da748ab2.a3ff151e  Sun, Feb 21 2016 13:12:50.640
filter delay:  0.19453  0.19344  0.19341  0.19354 
         0.00000  0.00000  0.00000  0.00000 
filter offset: -0.00252 -0.00223 -0.00296 -0.00309
         0.000000 0.000000 0.000000 0.000000
delay 0.19341, dispersion 0.00044
offset -0.002966

server 17.253.84.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.24779, dispersion 0.00063
transmitted 4, in filter 4
reference time:    da748ab2.077fa659  Sun, Feb 21 2016 13:12:50.029
originate timestamp: da748ab3.1f69b486  Sun, Feb 21 2016 13:12:51.122
transmit timestamp:  da748ab3.000ebedf  Sun, Feb 21 2016 13:12:51.000
filter delay:  0.24779  0.24857  0.24857  0.24823 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.011965 0.011501 0.011355 0.011109
         0.000000 0.000000 0.000000 0.000000
delay 0.24779, dispersion 0.00063
offset 0.011965

server 17.253.14.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.06609, dispersion 0.00035
transmitted 4, in filter 4
reference time:    da748aaa.d5225db1  Sun, Feb 21 2016 13:12:42.832
originate timestamp: da748ab2.af170bf9  Sun, Feb 21 2016 13:12:50.683
transmit timestamp:  da748ab2.a8bec679  Sun, Feb 21 2016 13:12:50.659
filter delay:  0.06775  0.06786  0.06865  0.06609 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.005122 0.004585 0.004944 0.004527
         0.000000 0.000000 0.000000 0.000000
delay 0.06609, dispersion 0.00035
offset 0.004527

server 17.253.54.251, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.14940, dispersion 0.00041
transmitted 4, in filter 4
reference time:    da748aac.bdf434ff  Sun, Feb 21 2016 13:12:44.742
originate timestamp: da748ab3.2c5f6146  Sun, Feb 21 2016 13:12:51.173
transmit timestamp:  da748ab3.1af31b15  Sun, Feb 21 2016 13:12:51.105
filter delay:  0.14940  0.14998  0.15178  0.15584 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.004575 0.004469 0.005269 0.002918
         0.000000 0.000000 0.000000 0.000000
delay 0.14940, dispersion 0.00041
offset 0.004575

server 17.253.38.253, port 123
stratum 1, precision -22, leap 00, trust 000
refid [GPSs], delay 0.17906, dispersion 0.00018
transmitted 4, in filter 4
reference time:    da748aaf.ba3c03ed  Sun, Feb 21 2016 13:12:47.727
originate timestamp: da748ab3.7ab88eb4  Sun, Feb 21 2016 13:12:51.479
transmit timestamp:  da748ab3.65d5b24e  Sun, Feb 21 2016 13:12:51.397
filter delay:  0.17940  0.18303  0.18025  0.17906 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.004901 0.006247 0.004883 0.004856
         0.000000 0.000000 0.000000 0.000000
delay 0.17906, dispersion 0.00018
offset 0.004856

server 17.253.12.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.07823, dispersion 0.00056
transmitted 4, in filter 4
reference time:    da748ab2.71e94c76  Sun, Feb 21 2016 13:12:50.444
originate timestamp: da748ab3.52ca2f7d  Sun, Feb 21 2016 13:12:51.323
transmit timestamp:  da748ab3.4aa5a469  Sun, Feb 21 2016 13:12:51.291
filter delay:  0.07823  0.07959  0.07927  0.07938 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.004089 0.004683 0.004710 0.004907
         0.000000 0.000000 0.000000 0.000000
delay 0.07823, dispersion 0.00056
offset 0.004089

server 17.253.4.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.08247, dispersion 0.00029
transmitted 4, in filter 4
reference time:    da748ab2.9c86971f  Sun, Feb 21 2016 13:12:50.611
originate timestamp: da748ab3.89a4a287  Sun, Feb 21 2016 13:12:51.537
transmit timestamp:  da748ab3.811904b3  Sun, Feb 21 2016 13:12:51.504
filter delay:  0.08247  0.08354  0.08432  0.08316 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.004894 0.005381 0.005089 0.004592
         0.000000 0.000000 0.000000 0.000000
delay 0.08247, dispersion 0.00029
offset 0.004894

server 17.253.34.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.14059, dispersion 0.00099
transmitted 4, in filter 4
reference time:    da748ab2.20438b82  Sun, Feb 21 2016 13:12:50.126
originate timestamp: da748ab3.f3cda148  Sun, Feb 21 2016 13:12:51.952
transmit timestamp:  da748ab3.e449ba5e  Sun, Feb 21 2016 13:12:51.891
filter delay:  0.14117  0.14233  0.15315  0.14059 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.002630 0.002604 0.008246 0.003099
         0.000000 0.000000 0.000000 0.000000
delay 0.14059, dispersion 0.00099
offset 0.003099

server 17.253.6.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.06593, dispersion 0.00092
transmitted 4, in filter 4
reference time:    da748ab0.6e7f416f  Sun, Feb 21 2016 13:12:48.431
originate timestamp: da748ab3.e2b4f880  Sun, Feb 21 2016 13:12:51.885
transmit timestamp:  da748ab3.dc14940b  Sun, Feb 21 2016 13:12:51.859
filter delay:  0.06708  0.07036  0.06593  0.06798 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.004849 0.005614 0.003835 0.004670
         0.000000 0.000000 0.000000 0.000000
delay 0.06593, dispersion 0.00092
offset 0.003835

server 17.253.2.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.06876, dispersion 0.00075
transmitted 4, in filter 4
reference time:    da748aaf.90dc62bd  Sun, Feb 21 2016 13:12:47.565
originate timestamp: da748ab4.18d780e7  Sun, Feb 21 2016 13:12:52.097
transmit timestamp:  da748ab4.11df43c7  Sun, Feb 21 2016 13:12:52.069
filter delay:  0.06931  0.06876  0.07674  0.06888 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.005531 0.005830 0.001524 0.005548
         0.000000 0.000000 0.000000 0.000000
delay 0.06876, dispersion 0.00075
offset 0.005830

server 17.253.52.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.14632, dispersion 0.00113
transmitted 4, in filter 4
reference time:    da748ab2.061595ca  Sun, Feb 21 2016 13:12:50.023
originate timestamp: da748ab4.97b9bf94  Sun, Feb 21 2016 13:12:52.592
transmit timestamp:  da748ab4.871cfbb9  Sun, Feb 21 2016 13:12:52.527
filter delay:  0.14799  0.14728  0.14632  0.14771 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.003221 0.003651 0.002333 0.003804
         0.000000 0.000000 0.000000 0.000000
delay 0.14632, dispersion 0.00113
offset 0.002333

server 17.253.26.253, port 123
stratum 1, precision -20, leap 00, trust 000
refid [GPSs], delay 0.08757, dispersion 0.00072
transmitted 4, in filter 4
reference time:    da748ab2.e54f6304  Sun, Feb 21 2016 13:12:50.895
originate timestamp: da748ab4.8e9150ca  Sun, Feb 21 2016 13:12:52.556
transmit timestamp:  da748ab4.8569e3c9  Sun, Feb 21 2016 13:12:52.521
filter delay:  0.08926  0.08757  0.08945  0.08951 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.005532 0.004636 0.005372 0.003800
         0.000000 0.000000 0.000000 0.000000
delay 0.08757, dispersion 0.00072
offset 0.004636

server 17.253.24.253, port 123
stratum 1, precision -19, leap 00, trust 000
refid [GPSs], delay 0.04640, dispersion 0.00031
transmitted 4, in filter 4
reference time:    da748aac.fbc2a34e  Sun, Feb 21 2016 13:12:44.983
originate timestamp: da748ab4.9e9d94bb  Sun, Feb 21 2016 13:12:52.619
transmit timestamp:  da748ab4.9a957470  Sun, Feb 21 2016 13:12:52.603
filter delay:  0.05292  0.04898  0.04640  0.04791 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.005614 0.004655 0.004368 0.004577
         0.000000 0.000000 0.000000 0.000000
delay 0.04640, dispersion 0.00031
offset 0.004368

server 17.253.20.253, port 123
stratum 1, precision -22, leap 00, trust 000
refid [GPSs], delay 0.07130, dispersion 0.00035
transmitted 4, in filter 4
reference time:    da748ab1.90646e72  Sun, Feb 21 2016 13:12:49.564
originate timestamp: da748ab4.e674782a  Sun, Feb 21 2016 13:12:52.900
transmit timestamp:  da748ab4.df764f11  Sun, Feb 21 2016 13:12:52.872
filter delay:  0.07245  0.07431  0.07130  0.07147 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.005126 0.005608 0.004607 0.004382
         0.000000 0.000000 0.000000 0.000000
delay 0.07130, dispersion 0.00035
offset 0.004607

21 Feb 13:12:52 ntpdate[17139]: adjust time server 17.253.24.253 offset 0.004368 sec