If you were to log in, you'd be able to get more information on your fellow community member.
The Software AG (http://www.softwareag.com/) in Germany has also a very impressive relational Database system called ADABAS. It is available on all main operating systems (including Linux). The database is mainly used in conjunction with the SAP system. Integration is available for C/C++, TCL, Perl and PHP/FI.
There is also a very good free alternative to sendmail on Unix: qmail, written by D.J. Bernstein. You can have a look at it at http://www.qmail.org/ . It doesn't come with any kind of management tools or a GUI but it is safe, easy to install and very fast in most situations. It is not made as an replacement for sendmail. Mr. Bernstein requires you to have some basic knowledge about the "Unix way" to use software. I use qmail on several Linux machines (all 486/33 with 16MB RAM) without any problems. SPAM filtering and virtual domains are included in qmail. If you are looking for a free REPLACEMENT for sendmail you probably have to wait for the initial release of Vmail, a project startet by Wietse Venema (http://wzv.win.tue.nl/vmail/).