On Tue, 21 Mar 2006 09:03:57 -0500, Michael DeGregory
<[log in to unmask]> wrote:

>It seems the probes are failing on valid email addresses though and I can't
>understand why. 

To learn this you have to do site-specific monitoring of the SMTP email
transaction with the receiving site(s) for the addresses in question.
Probe-Failed either means the address is truly not there (it should fail) or
the receiving site mail server (incorrectly) objects to the format of the
RFC821 return-path address:
MAIL FROM:<owner-nolist-xyz*mdegrego**LISTSERV*-AIP*[log in to unmask]>

If the site ojects to this return-path format, you can either give up on
mailing to such addresses or try to convince the receiving site to make
their mailer compliant with email standards RFC821 and RFC 2821 so they will
accept return-paths formatted in this way.

Since you are using LSMTP as your mailer, Site-Specific logging is easy. See
http://www.lsoft.com/manuals/lsmtp-faq.stm#2.6