... unfortunately no good news - just installed Version 2.1.a15 ...
~$ arpwatch - Version 2.1a15usage: arpwatch [-dN] [-f datafile] [-i interface] [-n net[/width]] [-r file] [-s sendmail_path] [-p] [-a] [-m addr] [-u username] [-R seconds ] [-Q] [-z ignorenet/ignoremask]
~$
