Network Warrior

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. ...