upsd is responsible for serving the data from the drivers to the clients. It listens on network ports and delivers the data from the state files or shared memory used by the drivers. It also conveys administration messages from the clients such as upsct2(8) or upscmd(8) back to the drivers.
This program is essential, and must be running at all times to actually make any use out of the drivers and clients.
stop - stop process and exit
Stay in the foreground for testing.
Display the help text.
Bind the listeners to the interface specified by its internet address. This may be useful in situations with internal and external interfaces on the same host.
Run the UDP and TCP listeners on that port. This overrides any value you may have set with 'configure --with-port'. If you don't change it with configure or this switch, upsd will listen on port 3305.
Switch to user user after startup if started as root. This overrides whatever you may have compiled in with 'configure --with-user'.
upsd can reload its configuration files without shutting down the process if you send it a SIGHUP or start it again with '-c reload'. This only works if the background process is able to read those files. Since upsd gives up root after reading the files for the first time, this may not always be the case.
If you think that upsd can't reload, check your syslogs for error messages. If it's complaining about not being able to read the files, then you need to adjust your system to make it possible. Either change the permissions on the files, or run upsd as another user that will be able to read them.
upsd expects the model drivers to update their status regularly. By default, they must be refreshed every 15 seconds. After that, the UPS is declared
The NUT (Network UPS Tools) home page: http://www.exploits.org/nut/