[Mimedefang] Getting MIMEDefang to Work

[Al Sparks]

New MIMEDefang user.

I've installed MIMEDefang on a system that already had sendmail
8.12.10 installed.  I did the necessary changes to get milter going
and re-compiled.  I hope.

I installed MIMEDefang using the CPAN install mechanism (i.e. I run
"perl -MCPAN -e shell" and at the prompt from there do the necessary
installation of MIMEDefang.

I already had SpamAssassin running on that system, and it was using
the procmail method of filtering.

I renamed the /etc/procmailrc that was calling spamc.

On spamassassin, I still have spamd running.

I also am using the example filter provided by the source,
    suggested-minimum-filter-for-windows-clients

I haven't added any code to it, just changed some variables at the
beginning.  Comments inside the file indicate that spamassassin is
getting called.

So my question is, how do I know anything is happening?

Specifically, to debug this, I'd like to be able to test if milter is
actually activated.  Suggestions on how to do that?

>From there, I'd like to go through the MIMEDefang filter and add some
headers to email just to see if it's working there.

This is a test email server, so I'm not worried about mangling email. 
I have to say that I'm not to sure about the way the mimedefang-filter
is setup.  To me, the code looks like a bunch of defined variables and
subroutines.  The way I see it, nothing is actually getting called. 
Yet according to the comments, it's supposed to be doing something
minimal.  Logs and full-header displays of my email don't indicate
anything is getting done.  I'll add that MIMEDefang does log to maillog
when it starts and stops, but nothing other than that.
   === Al