I downloaded the RPM, but it doesn't install. I get an error about failed dependencies. Red Hat Postfix FAQ Prev Chapter 3. Next 3.2 I downloaded the RPM, but it doesn't install. I get an error about failed dependencies.
Postfix is a replacement for sendmail.
Unless you install Postfix from source code the two cannot coexist on the same system. In order to get postfix to install you will have to remove sendmail first but there is a trick to doing this properly.