On UNIX, if the MFDS "Default process user ID" value is set, from either the GUI or with the mfds -f command line option, before the MFDS process starts, it will change its effective uid to the specified value after it has started listening on its configured endpoint. This enables the MFDS process to run using a non-root uid while still using the default privileged port 86. If the uid specified is invalid, the MFDS process terminates.