How do they share data with MBPs?

You send an email. Within seconds, filters at Gmail, Outlook, and Yahoo Mail are already checking it against shared intelligence from anti-abuse networks. But how does that intelligence actually get there?

The most common method is the threat feed. Anti-abuse organizations package up structured data and push it to mailbox providers (MBPs) on a regular schedule. These feeds contain IP addresses tied to spam activity, domains used in phishing, cryptographic signatures of known malicious campaigns, and indicators of a compromised sender. The format is typically machine-readable (think JSON or XML-style structured data) so filters can ingest it automatically without a human in the loop.

Speed matters here. A phishing campaign spotted at one inbox this morning could be blocked everywhere by afternoon. Some feeds push updates every few minutes. Others run hourly or daily depending on the severity of the threat and the data-sharing agreement in place.

Then there's the human layer. Groups like M3AAWG hold working sessions where security researchers from anti-abuse organizations sit in the same room (or virtual room) as MBP security teams. These conversations move faster than any formal data pipeline. Someone can say "we're seeing a coordinated campaign hitting our network right now" and MBPs can start acting on that before the official feed even updates.

It's not one-way either. MBPs contribute their own detection data back into shared pools. Gmail sees billions of emails a day. When its filters catch something new, that signal feeds back into the collective intelligence. The whole system gets smarter because each participant shares what they find.

There are also blocklist integrations worth knowing about. Organizations like Spamhaus and SpamCop maintain real-time DNS-based blocklists (DNSBLs) that MBPs query directly at filter time. If your IP or domain appears on one, every query returns a positive hit and that email is blocked or sent to spam. These aren't passive feeds. They're live lookups happening on every single message.

If you want to know whether your domain or sending IP is appearing in any of these systems right now, our free blocklist checker will tell you in about 30 seconds. Worth running if something feels off with your deliverability.