let's try that again:
/etc/postfix/mta_clients_dul.regexp contains on one line:
/(docsis|dsl|client|dhcp|pool|cpe|host|cust|dial|access|in\-addr|arpa|cable|nombres|upc\-[a-z]|user|bri\-).*\..*\.[a-z][a-z]/
554 ACL mta_clients_dul
And this will show you all connects to your IMGate where the MTA has a PTR,
on one line:
awk '/smtpd.* connect from/ {print $8 }' /var/log/maillog | egrep -iv
"unknown\[" | cut -d "[" -f 1 > /var/tmp/ptr.txt
