How do MBPs work with blocklists and anti-abuse orgs?

MBPs query blocklists during mail processing to inform filtering decisions. A sender listed on **Spamhaus SBL** will face delivery challenges across most major providers. MBPs also contribute data to blocklists by reporting spam sources identified through their filters.

Relationships go beyond simple queries. **MBP** postmaster teams participate in **M3AAWG** alongside blocklist operators. They collaborate on emerging threat response, share intelligence about new spam techniques, and coordinate policy changes. This creates aligned approaches across the ecosystem.

For senders, this integration means blocklist problems cascade. Getting listed on **Spamhaus** affects **Gmail**, **Microsoft**, and most other providers simultaneously. Conversely, maintaining clean standing with major blocklists provides ecosystem-wide benefits. Monitor blocklist status as part of regular deliverability hygiene.