Note: This page is quite old and is likely out of date. My opinions may have also changed dramatically since this was written. It is here as a reference until I get around to updating it.
Consider Postfix instead. It was written with security in mind.
yum install sendmail -y
Any configuration changes need to be
re-compiled by the m4 processor. This is
available in the
sendmail-cf package which can be install using the following
yum install sendmail-cf -y