This is a NFSv2-specific option.
The mapping daemon ugidd must be running.
In addition to the Trust remote users section, this option
allows you to specify a list of client UIDs to be treated as the
untrusted user. You must enter a comma-separated list
of UIDs or UID ranges like 1,10,20-25,100-150.
exportfs options: squash_uids, map_daemon