sets the system's date from a remote host with network time protocol

 OpenRdate or openrdate or rdate displays and sets the local date and time from
 the host name or address given as the argument. The time source may be an RFC
 868 TCP protocol server, which is usually implemented as a built-in service of
 inetd(8), or an RFC 5905 protocol SNTP/NTP server. By default, rdate uses the
 RFC 868 TCP protocol.
 .
 OpenRdate supports IPv4 and IPv6 protocols.