[Mimedefang] MIMEDefang versus CanIt-Pro versus Barracudas?

David F. Skoll dfs at roaringpenguin.com
Fri Nov 30 08:58:18 EST 2007

James Ralston wrote:

> Is anyone currently using CanIt-Pro or CanIt-Domain-Pro?

Yes! :-)

> Do those
> products offer the same flexibility as MIMEDefang in terms of being
> able to hook into sendmail via milter?  How well do the per-recipient
> Bayesian filters, whitelists, et. al. work?

OK.  This is coming from the lead developer of CanIt, so please remember
to ajust your non-neutral point-of-view filters.  I also apologize in
advance if anyone thinks I'm abusing the MIMEDefang list by plugging
our commercial products.

CanIt-PRO has per-recipient rules, filters, etc. and they work well.
The one caveat is that if an e-mail comes in for two recipients with
different sets of rules, we accept it at SMTP time and then process
copies separately for each recipient.  If the message winds up being
rejected by one (or both) recipients, we silently discard it.

Yes, it's against the spirit of the RFCs.  However, in our opinion,
preventing backscatter takes higher priority.  (You can always change
the default if you don't like it.)

With CanIt-PRO, you can give as much or as little control to end-users
as you like, all the way from "do nothing" to a few preset scanning
levels to fine-grained control.  CanIt-PRO users also get a
subscription to our RPTN service.  This is a daily-updated set of
Bayesian tokens derived from feedback from CanIt customers.
Currently, our database has tokens from about 900,000 e-mails, so you
start out with a huge Bayesian database that turns out to be pretty
accurate.  (Individual Bayes statistics are added to the central
database at analysis time.)

> I'm loathe to completely break such a fundamental aspect of mail
> delivery, so I'm wondering if CanIt-Pro would give us some of the
> "bullet points" of Barracudas but still retain the deep milter
> integration goodness...

What bullet points are you looking for?  Please see:


Or drop us a line at sales at roaringpenguin.com.

Please note that CanIt ships with source code and you're welcome to
tinker with it.  However, if you do make changes, it's up to you to
make sure they survive across upgrades.  That means you have to
be fairly disciplined about separating the custom code from the core.



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