This will test your mail server against 100+ DNS based email blacklists - commonly called realtime blacklist, DNSRBL or RBL. If your mail server has been blacklisted, email you send may not be delivered. Email blacklists are a common spam reduction technique.
Also included is a best practices checkup which looks for forward-reverse DNS matching, open relay checks, and IP reputation information.
I started using this service after many of our campaign emails weren't getting delivered to Yahoo. We quickly pin pointed the issue using the tools and are very happy with the constant updates which keep us in check to ensure delivery.Christine K.
Wearable Duds LLC