I am using one box as a dns/web server and another as a mailserver. I setup the dns records, but they don't seem to be working. When I look up the DNS records, it says they are "lame". It says the DNS is not answering authoritatively. I can send and receive email just fine using webmail. When I use a client, mail appears to send ok, but no one ever actually receives it. It never gives me an error to receive mail either. It just doesn't receive anything. The domain I am working with is rwhm.net. Web seems to be working just fine.
Your DNS server has to be authoritative for your domain! When you registered your domain, you had the chance to specify some name servers for it. Maybe the company where you registered your domain has a control panel where you can change the DNS servers.