I've got a Postfix/Courier mail server (Authenticated with SASL/MySQL) all according to this tutorial. I'm currently running my server on Debian 6, it is a VPS. It works well as far as I can see but I can't seem to require authentication for inbound email sending.
CentOS 6.5 is based on the upstream release EL 6.5 and includes packages from all variants. There are many fundamental changes in this release, compared with the past CentOS 6 releases and we highly recommend everyone study the release notes as well as the upstream technical notes about the changes and how they might impact your installation.