Setup email on Linux/Kloxo

I can't get email working on my VPS hosting. It has kloxo installed by the hosting company but I can't seem to get email to send. I am trying to send email from Railo code and I have done this successfully on another server I can provide the code for testing. You shouldn't need to know Railo or coldfusion but just be able to setup the email correctly. Everything is installed on the server but I think its just that I have done something wrong in the DNS. I was trying to sort out spf records and this is probably what has caused it to stop working. If you know how to setup DNS, spf and kloxo email settings it should be relatively easy. I would ideally want the spf setup and if you can setup domain keys too that would be great.