i have just followed the howto doc as posted on this site word for word.
i think the dfilt is for disclaimer and this is the value
dfilt unix - n n - - pipe
flags=Rq user=filter argv=/etc/postfix/disclaimer -f ${sender} -- ${recipient}
the whitelist entry was also posted in the how to doc
http://www.howtoforge.com/the-perfec...ick-meerkat-p4