xntpd on SCO system machines supports a special pseudo-time server used for backup or when no other clock source is available (for example, if Internet access is not available). This feature can be used to run an isolated NTP synchronization network, where standard time source is not available, or is only intermittently available. This server is set as follows in the /etc/inet/ntp.conf file:
server 127.127.1.unit # Synchronization with local RTC fudge 127.127.1.unit stratum levelThese lines allow a server to synchronize with its own real-time clock. The unit number of the clock is usually set to 0. The local clock is usually configured at a high level stratum such as 10. This will minimize problems if it is being used as a backup, or if Internet connectivity is re-acquired. Since the local clock is not connected to a reliable time source such as the Global Positioning System (GPS) or a radio signal, configuring it at an elevated stratum allows it to be overlooked if more accurate servers are available.
Note that the server, when synchronized to this pseudo-time server, will advertise a stratum one greater than that of the pseudo-time server. This allows peers and clients to recognize that the reliability of the service has changed.
The following lines from /etc/inet/ntp.conf illustrate how a server can be configured to use its own clock if necessary:
server 127.127.1.0 # allow synchronization with local clock fudge 127.127.1.0 stratum 10 # but fudge the stratum to a low level