@Sed,

Yes, you are right the “restrict” directive was employed in the previous configuration of the ntpd server. It’s possible that it still holds relevance for legacy purposes in the chrony.conf file.

I am a bit surprised on the restrict directive. On chrony.conf manual it is not mentioned and on red hat official documentation neither.

My understanding is that the allow directive is used in chrony.conf file to enable your computer to be a ntp server (https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-configuring_ntp_using_the_chrony_suite#sect-Understanding_the_chrony_configuration_commands)

To me the restrict directive was used in former ntpd server configuration. Maybe it is still valid for legacy purpose?