First you’ll want to use MX Toolbox’s SuperTool… a very handy and completely free online tool that allows you to perform many important domain and IP related activities, including check all known blacklists for your IP’s inclusion. You can find the tool at mxtoolbox.com/SuperTool.aspx and there you will see a complete list of commands and what they do. In order to run a blacklist check, enter “blacklist: (ip)” (replace (ip) with your server’s IP duh!) and click the lookup button to run the check. Should you get any positive hits and you ARE indeed blacklisted, they will be listed at the top with a red icon and you can contact them directly and asked to be removed. A clean bill of health will look like this: