Here is some more information on how our blacklist detection works.

What is a blacklist? A blacklist is an online database that aggregates email addresses and domains that have been reported on multiple occasions to be sending out spam or malicious content to others on a large scale. These blacklists are used as a reference by mail servers to determine how safe it is to accept messages coming from unknown domains and addresses.

How Do You Get On A Blacklist? Inboxes and domains end up getting listed on blacklists when

1. The domain receives a high amount of complaints for sending spam

2. The domain attempts to send out a large amount of emails that bounce

How we identify that you're on a blacklist

Once you sync an inbox to our platform, we check the IP address of your domain against to 4 most common IPv4 blacklists that spam filters utilize when verifying the validity of incoming mail. If we ever have a confirmed match that your IP address is listed on any of these blacklists, it will be displayed on the primary dashboard of your Warmup Inbox account.

Other Resources Our blacklist detector covers a lot of providers, but if you want to get another look you can reference the free tool MxToolBox. They cover a few more blacklists that we currently do not track.