Domain Time Dialup Monitor (DTDialup) is a companion program for Domain Time Server, for use in
situations where the service does not have full-time access to its time source, but uses Dial-Up Networking
instead. DTDialup monitors the connected state of the machine, and signals the Domain Time II Server to synchronize
when a connection is established.
Contact your Symmetricom representative to obtain a free copy of this utility.
How to use the Dialup Monitor
Normally, servers have a full-time connection to their time sources, whether on the Internet or on a private network. Servers SHOULD have a full-time connection (or at
least demand-dial), because they need to check as often as necessary to ensure that their clocks are stable and reliable.
Clients have dial-up awareness built in, but servers do not because they are expected to be online continuously. DTDialup works alongside Domain Time Server to
trigger a sync as soon as a dial-up connection is established. When the DTDialup
service starts, it modifies the Domain Time Server configuration as follows:
- Disables Domain Time Server's accuracy-seeking algorithms (default is
enabled).
- Tells Domain Time Server not to get time from an external source (default
is to use an external source).
- Tells Domain Time Server to serve the time to clients whether or not the
server's time has been verified (default is to refuse this).
Installing DTDialup on a slave server will have no effect, since slaves replicate
settings from the master, and always refuse to serve the time until their own clocks
have been set.
DTDialup checks the server settings every time it starts, and makes the appropriate
changes, including restarting Domain Time Server if necessary to allow it to start
serving the time immediately.
It then starts checking for a RAS dial-up connection. If you are offline, DTDialup
checks every 5 seconds, waiting for you to go online. When DTDialup detects that
you have gone online, it then waits an additional 15 seconds, and, if you are still
online, signals the Domain Time Server to synchronize. The additional wait is to
give your connection time to initialize, authorize, and establish new routes.
When DTDialup signals Domain Time Server to synchronize, it performs the following actions:
- Tells Domain Time Server to get its time from an external source (using
whatever sources and protocols you have specified on the control panel
applet).
- Sends a CPL signal to inform Domain Time Server that a synchronized is wanted.
- Waits a few seconds, then turns the use-external-source checkbox off again.
While you are online, DTDialup checks every 5 minutes, waiting for you to go offline.
The 5-minute interval is used to prevent unnecessary checks due to redials or
jittery connections. Once you are offline, DTDialup goes back to checking every
5 seconds for you to go online again.
The net effect is that, approximately 15-20 seconds after any successful dialup, the
Domain Time Server will synchronize with your selected time source, but not more
than once during any 5-minute period.