In looking at your spam reduction info in your FAQ you have this.
Configure the SMTP connector to use one or two RDNS blacklist providers; since this will prevent you receiving spam from known spammer IP addresses. Spamhaus Zen and Barracuda blacklist are recommended. Be aware that you must register with Barracuda to use their blacklist. When using a blacklist, make sure you are using your own DNS IP address in your SMTP options. If you use an external DNS such as 8.8.8.8 from Google then reverse DNS blacklisting will not work.
I am registered at Barracuda with my IP address of the mail servers and my local DNS servers however my DNS servers (Windows DNS) have recursion off so it can only respond with local zone queries. You say not to use an external DNS like 8.8.8.8 as the RBL will not work. Does this mean that I need to set up another DNS server on another server here that is recursive and use that one for SMTP queries?
I am also using MagicSpam does this effect it or does it work some other way?
Thanks,
Phil