What is Spamhaus and why is it so influential?

Spamhaus overview:

What it is:

Non-profit organization tracking spam sources

Maintains multiple blocklists (SBL, XBL, DBL, PBL)

Provides data to email providers worldwide

Why it matters:

Used by most major ISPs and email providers

Trusted industry standard

High-quality, well-maintained lists

Spamhaus lists:

SBL: Known spam sources

XBL: Exploited/compromised IPs

DBL: Domain blocklist

PBL: Policy blocklist (dynamic IPs)

Impact of listing:

Widespread delivery failure

Cannot be ignored

Must address seriously

Spamhaus listing is the most serious blocklist event.

The most influential harbor authority. Their bans affect nearly every port.