Blacklist monitoring across 14 sources

Updated Apr 4, 2026 · 5 min read

Which blacklists Inboxlee monitors, why these specifically, and what to do on a hit.

On this page · 2

Sources we monitor
On a hit

There are over 100 publicly tracked blacklists. Most have negligible impact on cold-email placement. Inboxlee monitors the 14 with measurable correlation to Gmail, Workspace, M365, and Yahoo placement decline.

Sources we monitor

Spamhaus SBL - IP-level spam source listing.

Spamhaus DBL - domain-level abuse listing.

Spamhaus XBL - exploit/compromise listing.

Spamhaus PBL - policy-block listing for non-MTA IPs.

SURBL - URL/domain reputation across multiple feeds.

URIBL - URL block list.

Barracuda Reputation Block List.

SpamCop Block List.

SORBS DUHL/SPAM - Composite Blocking List.

Mailspike - high-volume sender reputation.

Truncate.gbudb - fast-feed dynamic listing.

Hostkarma blackboxes.

NixSpam.

WPBL - Weighted Private Block List.

On a hit

A new listing fires an immediate dashboard alert plus optional email or webhook. The alert includes the source, the affected domain or IP, and a remediation path (delisting URL, suggested sender pattern review, mailbox suspension recommendation if compromise is suspected).

Most listings auto-clear after 24–72 hours of clean sending behavior. Spamhaus listings sometimes require a manual delisting request - we provide the pre-filled form.

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