What is Blocklist and how can it help?

Question

What is Blocklist and how can it help?

Answer

Blocklist Monitoring checks whether your server's IP address has been added to any Real-time Blackhole Lists (RBLs), also called blocklists. These are databases that mail servers worldwide consult to decide whether to accept, reject, or mark incoming email as spam.
 
The feature runs automated periodic lookups of your IP against multiple RBL providers. If your IP gets listed on any of them, you receive an alert immediately, so you can request delisting before it causes significant email delivery problems. Without this, an IP can sit blocklisted for days before anyone notices - so it is a useful tool to have.