DNS and Time Sync DIY Labs

Lab: Configure Chrony

  • Install Chrony and mark the service for autostart on reboots. systemctl enable --now chronyd

  • Edit the Chrony configuration file and comment all line entries that begin with “pool” or “server”.

[root@server10 ~]# vim /etc/chrony.conf

  • Go to the end of the file, and add a new line “server 127.127.1.0”.

  • Start the Chrony service and run chronyc sources to confirm the binding.

[root@server10 ~]# systemctl restart chronyd

[root@server10 ~]# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^? 127.127.1.0                   0   6     0     -     +0ns[   +0ns] +/-    0ns

Lab: Modify System Date and Time

  • Execute the date and timedatectl commands to check the current system date and time.
[root@server10 ~]# date
Mon Jul 22 11:37:54 AM MST 2024

[root@server10 ~]# timedatectl
               Local time: Mon 2024-07-22 11:37:59 MST
           Universal time: Mon 2024-07-22 18:37:59 UTC
                 RTC time: Mon 2024-07-22 18:37:59
                Time zone: America/Phoenix (MST, -0700)
System clock synchronized: no
              NTP service: active
          RTC in local TZ: no

  • Identify the distinctions between the two outputs.

  • Use timedatectl and change the system date to a future date.

[root@server10 ~]# timedatectl set-time 2024-07-23
Failed to set time: Automatic time synchronization is enabled

[root@server10 ~]# timedatectl set-ntp false

[root@server10 ~]# timedatectl set-time "2024-07-23"
  • Issue the date command and change the system time to one hour ahead of the current time.
[root@server10 ~]# date -s "2024-07-22 12:41"
Mon Jul 22 12:41:00 PM MST 2024
  • Observe the new date and time with both commands.
[root@server10 ~]# date -s "2024-07-22 12:41"
Mon Jul 22 12:41:00 PM MST 2024

[root@server10 ~]# date
Mon Jul 22 12:41:39 PM MST 2024
[root@server10 ~]# timedatectl
               Local time: Mon 2024-07-22 12:41:41 MST
           Universal time: Mon 2024-07-22 19:41:41 UTC
                 RTC time: Tue 2024-07-23 07:01:41
                Time zone: America/Phoenix (MST, -0700)
System clock synchronized: no
              NTP service: inactive
          RTC in local TZ: no
  • Reset the date and time to the current actual time by disabling and re-enabling the NTP service using the timedatectl command.
[root@server10 ~]# timedatectl set-ntp true