Licensing


It's all Free Software:

Sendmail
Basically, Free Software/Open Source (BSD)
ftp.sendmail.org/pub/sendmail/LICENSE
But, dual licensed by Sendmail, Inc (comparable to MySQL AB)
www.sendmail.org/license-info.html

Perl
Perl Artistic License
www.perl.com/language/misc/Artistic.html

MIMEDefang
GNU General Public License
www.roaringpenguin.com/gpl.txt