Andreas Stiasny - EzineArticles.com Expert Author

How Useful Are DNS Block Lists?
[Internet-and-Businesses-Online:Spam-Blocker] DNS-based spam databases also known as DNS block lists are a very effective tool to keep the amount of spam that reaches the inboxes of the users low. They are a server side tool integrated into the mail server configuration. But they are dangerous too because if you are not careful enough you may reject wanted mails also.