Spamhaus is a nonprofit organization that maintains the world's most widely used email blocklists — databases of IP addresses and domains linked to spam or abuse. Mailbox providers and firewalls check incoming mail against Spamhaus lists such as the SBL, XBL and DBL, and mail from a listed source is commonly rejected or filtered, so a Spamhaus listing can sharply cut deliverability.
How Spamhaus works
Spamhaus operates several DNS-based blocklists (RBLs). The SBL lists IPs linked to spam sources, the XBL covers infected or hijacked machines, and the DBL is a domain blocklist. When a receiving server accepts a message, it queries these lists in real time; a match on any of them can block the message. Spamhaus also runs spam traps, so a listing often follows poor list hygiene rather than deliberate spamming.
Why Spamhaus matters and how to stay off it
Because so many providers rely on it, staying off Spamhaus is essential to a healthy sender reputation. Send only to opted-in contacts, authenticate your domain, and remove hard bounces and inactive addresses promptly. Mailpro monitors its sending IPs against Spamhaus and other blocklists and reroutes traffic before a listing affects you. Learn how to monitor blocklists, read the email blacklist guide, or explore Mailpro's anti-spam tools.
Mailpro and Spamhaus
Sending IPs monitored against Spamhaus, around the clock
Mailpro tracks all its sending IPs against Spamhaus and every other major blocklist, and reroutes traffic before a listing can affect your delivery — reputation management handled for you.