Shorewall users - Oct 2003 - daily mail rejected by spam filters

Here are the mail logs detailing mail messages that were rejectect by
our spam filters.  Users with an istop.com userid can bypass the spam
filters by having mail sent to userid@ca.istop.com.  If you have your
own domain name contact support@istop.com if you wish to have the
spam filters turned off for your domain. 

Oct 24 22:08:27 ns postfix/smtpd[29270]: reject: RCPT from
sklav.dsl.istop.com[66.11.173.180]: 504 <ezoi2>: Helo command rejected:
need fully-qualified hostname; from=<sklav@istop.com>
to=<shorewall-users@lists.shorewall.net>