June 2007
Intermediate to advanced
600 pages
18h 19m
English
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Configuring NTP
NTP is a client/server application. Devices participating in NTP are either NTP servers, which provide time to other devices, or NTP clients, which request time from NTP servers. Servers are also clients, and can be peered with each other as well. Configuring an IOS device as an NTP client is the simpler of the two models, so we'll start there.
NTP Client
To configure an IOS device to request accurate time from an NTP server, use the
ntp server command. You can list as many NTP
servers as you need, each on a separate line. Here, I've listed seven publicly available
NTP servers. Using so many will help illustrate how NTP behaves:
ntp server 132.163.4.102 ntp server 193.67.79.202 ntp server 152.1.58.124 ntp server 128.118.46.3 ntp server 129.6.15.29 ntp server 64.236.96.53 ntp server 208.184.49.9
Once you've configured the NTP servers, you should begin receiving accurate time signals (assuming you can reach them).
To see the statuses of the servers, and the time they are providing, use the command
show ntp associations:
2950#sho ntp associations address ref clock st when poll reach delay offset disp +˜132.163.4.102 .ACTS. 1 373 1024 377 109.0 1.10 0.7 ˜193.67.79.202 .GPS. 1 419 1024 377 282.7 81.38 81.6 ˜152.1.58.124 0.0.0.0 16 - 1024 0 0.0 0.00 16000. ˜127.127.7.1 127.127.7.1 7 16 64 377 0.0 0.00 0.0 ˜128.118.46.3 0.0.0.0 16 - 1024 0 0.0 0.00 16000. -˜129.6.15.29 .ACTS. 1 539 1024 277 22.4 −4.63 3.0 +˜64.236.96.53 .ACTS. 1 255 1024 377 20.9 1.80 24.7 *˜208.184.49.9 .ACTS. ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.