This allows you to verify a system's time has not be altered by comparing it to the time on a specified Internet time server. Sometimes, the availability of time servers may be somewhat unreliable (which is why this class allows you to specify multiple servers as fallbacks), and it is common for SNTP requests to be blocked by firewalls and proxy servers.

Additionally, although it is technically possible to perform SNTP requests against public NTP servers in your application, we strongly recommend you get approval from the time server's administrators/owners first (as this could cause unexpected load on their time servers, which could cause problems for you and everyone else who might rely on them).