Originally Posted by AndrewX

Different mail servers have different filtering capabilities. When you go for shared hosting, you are stuck with what the host has installed on the shared server or what the control panel they have depends on. I believe cPanel (which we offer as an addon) only runs with Exim mail server for example (also CentOS only, no 'light weight' possibilities like Debian). Postfix (our default) mail server has good ones: http://www.postfix.org/addon.html - that having said I don't know what Amerinoc uses for mail, but I'm sure they also have good filter capabilities available. Talk to them if they want to install some addon for you.