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CCNA Recap: NTP (Network Time Protocol)

This is a new series where I revisit CCNA topics for remembrance and explanation. A mix of old and new notes.

There are thousands of NTP servers around the world with access to atomic and GPS clocks (Very precise clocks), synchronised with Coordinated Universal Time.


NTP clients initiate a request with a server, and the client updates about once every 10 minutes on port 123.

NTP synchronize the clock times on computers and devices within a network. Why is this important? From updates to security (though NTP has its flaws), Timing matters.

It's possible to have Time of Day restrictions to network resources.

If you receive an alert that someone is on the network after hours, but your time isn't synchronized correctly, how do you know if someone is simply working past clock-out time after being logged in all day, or has truly logged in at 11 PM?






Older notes:

ntp server enables network time protocol function.

clock timezone [TMZ [In Relation to UTC]]
———————————
clock [season-time][TMZ] [recurring]
———————————
Use the ‘?’ to figure this one out

clock set HH:MM:SS D MONTH YEAR

NTP Server: Here’s the time. Adjust it yourself
NTP Clients: Ok, adjusting….adjusting….
NTP Client/Servers: Here’s the time you over here, meanwhile I’ll get my time as a client from this server over here. In a completely different direction

To be A NTP Clent
    * ntp server [xxx.xxx.xxx.xxx | hostname]
                * this IP / ho represents the server’s IP or hostname

Trusted clock source in a Cisco-only network, you tell a ntp router that “Hey, you are a trusted and valuable source,” by giving it the ntp master command.

show commands
* show ntp status
    * clock is synchronized
    * reference is X.X.X.X
    * Time and date
* show ntp associations
    * shows an ip address
    * * = the router has peered with said ip w/ NTP as an association




source: Old notes, SearchNetworking

EMPLOYERS: This is me reviewing things I have been tested on in the past.
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