Learn how domain reputation, DMARC compliance, and public blocklists affect your inbox placement.
Unlike legacy IP-based blacklists that only check the sending mail server, modern spam filters inspect the domain names found in the "From" header, Return-Path, DKIM signatures, and message links. Dmarckly directly queries these authoritative zones:
Maintained by The Spamhaus Project. Flags domains with poor reputation, phishing, malware delivery, or fraudulent registration.
Zone:[domain].dbl.spamhaus.org
Tracks domain names and website URIs found in unsolicited emails across Black (high spam confidence), Grey, and Red lists.
Zone:[domain].multi.uribl.com
Aggregates malicious links, cracked sites, phishing domains, and malware distribution points seen in unsolicited bulk email.
Zone:[domain].multi.surbl.org
A real-time reputation feed providing explicit classification: Whitelist (good), Blacklist (bad), Yellow (mixed), and Brown.
Zone:[domain].hostkarma.junkemailfilter.com
p=none satisfies the minimum verification requirement, it provides zero protection against spoofing. Attackers can freely forge your domain name. Reaching p=reject completely instructs mail servers to drop fraudulent mail before it reaches users.
include:, a, mx, redirect). If an SPF record cascades through multiple services (e.g., Google + SendGrid + Zendesk + HubSpot) and exceeds 10 lookups, receivers abort with PermError and SPF validation fails completely.
To view internal mailbox reputation directly from mailbox providers, verify your domain in these free portals: