Jeremy's IT Lab CCNA NTP Day 37

[...] = UDP port 123

NTP

A device [can/can't] be an NTP server and client at the same time.

can

Anything above NTP stratum [...] is considered unreliable and the device will not sync its time.

15

Configure NTP symmetric active mode:

R1(config)# [...]

ntp peer ip-address

Configure recurring daylight saving time:

R1(config)# [...]

clock summer-time name recurring start end [offset]

(start and end require the week (first, last, or number), weekday, month, and time)

Configure the device to be an NTP server:

R1(config)# [...]

ntp master [stratum]

Configure the hardware clock:

R1# [...]

calendar set hh:mm:ss day month year

(day and month can be reversed in order)

Configure the NTP server to sync to:

R1(config)# [...]

ntp server ip-address [prefer]

Configure the router to update the hardware clock using NTP:

R1(config)# [...]

ntp update-calendar

Configure the software clock:

R1# [...]

clock set hh:mm:ss day month year

(day and month can be reversed in order)

Configure the source interface of NTP messages:

R1(config)# [...]

ntp source interface

Configure the timezone:

R1(config)# [...]

clock timezone name hours-offset [minutes-offset]

Create an NTP authentication key:

R1(config)# [...]

ntp authentication-key key-number md5 key

Display the hardware clock:

R1# [...]

show calendar

Display the software clock, including the time source:

R1# [...]

show clock detail

Display the software clock:

R1# [...]

show clock

Display the status of NTP on the device:

R1# [...]

show ntp status

Displays the logs of the device:

R1# [...]

show logging

Enable NTP authentication:

R1(config)# [...]

ntp authenticate

Make the hardware clock update to match the software clock's time:

R1# [...]

clock update-calendar

Make the software clock update to match the hardware clock's time:

R1# [...]

clock read-calendar

NTP = [...] port 123

UDP

NTP = UDP port [...]

123

NTP servers directly connected to reference clocks are stratum [...]

1

NTP servers which get their time directly from reference clocks are also called [...].

primary servers

NTP servers which get their time from other NTP servers are called [...].

secondary servers

NTP servers with a [lower/higher] stratum are preferred.

lower

NTP uses only the [...] time zone.

UTC

Reference clocks are NTP stratum [...]

0

Show a list of configured NTP servers:

R1# [...]

show ntp associations

Specify an NTP trusted key:

R1(config)# [...]

ntp trusted-key key-number

Specify the NTP authentication key to use with the NTP server:

R1(config)# [...]

ntp server ip-address key key-number

The default stratum of the ntp master command is [...].

8

The distance of an NTP server from the original reference clock is called [...].

stratum

What does NTP stand for?

Network Time Protocol

What is the default time source for the software clock of a Cisco device?

hardware calendar

What is the default time zone on Cisco devices?

UTC (Coordinated Universal Time)

What is the meaning of an asterisk (*) next to the time in the output of show clock?

The time is not authoritative

When an NTP server peers with another server at the same stratum level, this is called [...] mode.

symmetric active