H.5. Other configuration options

NUT data server port


Change the TCP port used by the network code. Default is 3493 as registered with IANA.

Ancient versions of upsd used port 3305. NUT 2.0 and up use a substantially different network protocol and are not able to communicate with anything older than the 1.4 series.

If you have to monitor a mixed environment, use the last 1.4 version, as it contains compatibility code for both the old "REQ" and the new "GET" versions of the protocol.

Daemon user accounts


See also --enable-inplace-runtime.

Programs started as root will setuid() to <username> for somewhat safer operation. You can override this with -u <otheruser> in several programs, including upsdrvctl (and all drivers by extension), upsd, and upsmon. The "user" directive in ups.conf overrides this at run time for the drivers.


upsmon does not totally drop root because it may need to initiate a shutdown. There is always at least a stub process remaining with root powers. The network code runs in another (separate) process as the new user.

The <groupname> is used for the permissions of some files, particularly the hotplugging rules for USB. The idea is that the device files for any UPS devices should be readable and writable by members of that group.

The default value for both the username and groupname is nobody (or nogroup on systems that have it when configure script runs). This was done since it’s slightly better than staying around as root. Running things as nobody is not a good idea, since it’s a hack for NFS access. You should create at least one separate user for this software.

If you use one of the --with-user and --with-group options, then you have to use the other one too.

See the INSTALL.nut document and the FAQ for more on this topic.

Syslog facility


Change the facility used when writing to the log file. Read the man page for openlog to get some idea of what’s available on your system. Default is LOG_DAEMON.