Users could specify the list of NTP servers that they want using "redfish/v1/Managers/<instance>/NetworkProtocol". However, there is not a method to verify if those NTP servers are actually reachable in the network and are working correctly.
Would Redfish be interested in having a mechanism where we can send a "Validate NTP servers" request via redfish and the backend implementation could use NTPQ for example.
I'd like to see a proposal for additions to the NTP configuration object that could report the "status/state" of the NTP functionality. It's different than the rest of the protocols shown in the ManagerNetworkProtocol resource in that the service is a consumer of the protocol, not a provider. So this information would be tailored to NTP - something like "NTPServerStatus" and perhaps a timestamp of the last contact?
I think that would be more generally useful as the service should be using the protocol regardless of any manual user checks. So reporting that information is a good first start. If that alone doesn't solve the use case, then we can look at a mechanism to launch a "check".