02-07-2017 10:12 AM - edited 03-08-2019 09:13 AM
when configuring the NTP Client:
ntp server X.X.X.X
whose address is the X.X.X.X?
also, at least in Packet Tracer, there is this weird "key" part of the command that's not in any study material i'm reading...
ntp server X.X.X.X <key>
what is that?
Packet Tracer ALSO lacks the ntp master command so I don't know if ntp can even work.
Solved! Go to Solution.
02-07-2017 04:24 PM
Hi Josh,
No worries, please let me share an example, we are going to configure 2 routers with NTP, R1 will be the ntp server and R2 ntp client.
R1
ntp master
ntp authentication-key 1 md5 HELLO <-- configure authentication and it is assigned to one identifier, in few words key 1.
No we configure the client to sync the time using R1
R2
ntp authenticate
ntp authentication-key 1 md5 HELLO
ntp trust-key 1
ntp server 1.1.1.1 key 1
So R2 will be able authenticate with the NTP server only if it uses the same key id provided by R1 (NTP server), in this case key 1
Hope it is useful :-)
02-07-2017 10:52 AM
Hi
Ntp server <ip address or domain name> this command is used to sync the time with a public NTP server or a NTP server used to sync with a public server.
ntp server x.x.x.x key : is used when you are going to set up authentication with the ntp server. This link could be useful: http://www.packetu.com/2008/12/28/ntp-authentication-ciscos-implementation/
ntp master is used to configure the Cisco IOS software as a Network Time Protocol (NTP) master clock to which peers synchronize themselves when an external NTP source is not available. This link could be useful: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/bsm/command/bsm-cr-book/bsm-cr-n1.html#wp3294676008
Hope it is useful :-)
02-07-2017 02:57 PM
i'm still confused
i know about ntp trusted key and ntp authentication-key
but when would i need to configure the "key" after ntp server X.X.X.X?
02-07-2017 04:24 PM
Hi Josh,
No worries, please let me share an example, we are going to configure 2 routers with NTP, R1 will be the ntp server and R2 ntp client.
R1
ntp master
ntp authentication-key 1 md5 HELLO <-- configure authentication and it is assigned to one identifier, in few words key 1.
No we configure the client to sync the time using R1
R2
ntp authenticate
ntp authentication-key 1 md5 HELLO
ntp trust-key 1
ntp server 1.1.1.1 key 1
So R2 will be able authenticate with the NTP server only if it uses the same key id provided by R1 (NTP server), in this case key 1
Hope it is useful :-)
02-08-2017 12:36 AM
alright, good
i had to make sure i wasn't putting too many keys in
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