upsd - UPS information server


upsd -h

upsd -V

upsd [-p__ ''port''__? [-t__ ''port''__? [-i__ ''interface''__? [-f? [-u__ ''user''__? [-c__ ''command''__?


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.

Controls in the configuration files allow you to limit access to the server, but you should also use a firewall for extra protection. Client processes such as upsmon(8) trust upsd for status information about the UPS hardware, so keep it secure.


  • c command

Send command to the background process as a signal.

Valid commands are
reload - reread configuration files

stop - stop process and exit

  • f

Stay in the foreground for testing.

  • h

Display the help text.

  • i interface

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.

  • p port

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.

  • t port

Run just the TCP listener on that port. If you want the TCP and UDP listeners on different ports for some reason, use

  • p, then follow it with -t.
  • u user

Switch to user user after startup if started as root. This overrides whatever you may have compiled in with 'configure --with-user'.

  • V

Display the version of the program.


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.

DO NOT make your upsd.conf world-readable, as it contains passwords and some evil person could pretend to be your master upsmon and command your systems to shut down.


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

If upsd complains about staleness when you start it, then either your driver or configuration files are probably broken. Be sure that the driver is actually running, and that the UPS definition in ups.conf(5) is correct.


The general upsd configuration file is upsd.conf(5). The administrative functions like SET and INSTCMD for users are defined and controlled in upsd.users(5). UPS definitions are found in ups.conf(5).



upsc(8), upscmd(8), upsct(8), upsct2(8), upslog(8), upsmon(8)

CGI programs:

upsset.cgi(8), __multimon.cgi__(8)?, upsstats.cgi(8), __upsimage.cgi__(8)?


nutupsdrv(8), apcsmart(8), belkin(8), bestups(8), powercom(8)

Internet resources:

The NUT (Network UPS Tools) home page:

NUT mailing list archives and information:

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