Directory of every major email blocklist (DNSBL / RBL) used by mail operators worldwide. Listing criteria, scope, removal procedures and DNSBL zone for each, so you can choose which to query and explain to a sender why their message bounced.
Barracuda's public-facing reputation list. Requires registration to query (a registered referrer IP). Useful as a secondary check alongside Spamhaus.…
Now part of the Spamhaus XBL list. Maintained as a standalone interface for legacy users; new deployments use Spamhaus ZEN directly.…
Reputation-style list with graded responses. Useful for scoring rather than blocking. Small operator; lower coverage than the major lists.…
Commercial list aimed at filling gaps left by free lists. Not free for any use; subscription required.…
Pure block-list view of Mailspike's data. Binary instead of graduated. Useful when the mail filter wants a yes/no answer rather than a reputation score.…
Reputation list (rather than pure blocklist) returning a score for each IP. Useful as a scoring input in mail filters that support graduated decisions.…
Maintained by a small team; conservative listing criteria emphasise correctness over coverage. A useful complement to higher-coverage lists like Spamhaus.…
Spam and Open-Relay Blocking System. Operated by Proofpoint after acquiring it. Multiple sub-zones available; dnsbl.sorbs.net is the aggregate. Notably stricter listing criteria than Spamhaus; some operators consider it …
Long-running blocklist driven by user spam reports. Operated by SpamCop, owned by Cisco since 2007. Useful as a complaint-driven complement to evidence-based lists.…
Spamhaus' domain-name list. Standard inclusion alongside ZEN in modern mail filtering.…
Policy Block List. Lists IP ranges that ISPs have declared should not send mail directly. Maintained from registry data.…
The de facto industry-standard IP blocklist. Used by the vast majority of mail servers worldwide as the first-line check. Free for personal and small commercial use; paid datafeed available for large operators.…
Zero-Reputation Domains list. Heuristic signal for newly-observed domains in messages, often a strong spam indicator.…
The dominant URL-based blocklist. Matches against domains and URLs in message body, not IPs in headers. Complementary to Spamhaus DBL.…
German anti-spam project. Three levels of escalation: L1 (individual IPs), L2 (entire /24 blocks), L3 (entire ASes). L1 is the most commonly used; L2 and L3 are aggressive and have higher false-positive rates.…
UCEPROTECT escalation level 2. Listing extends to the whole /24 once enough IPs within are L1-listed. Aggressive and prone to collateral damage; use with caution.…
UCEPROTECT escalation level 3. Whole-ASN listing; the most aggressive of the three. Rarely used as a hard block; some operators use it as a scoring input only.…
In total there are 66 users online: 0 registered, 61 guests and 5 bots.
Users active in the past 15 minutes. Total registered members: 396
Cookie preferences
Each category below sets a Google Consent Mode v2 signal. Necessary cookies cannot be switched off because they keep the site working. Everything else defaults to off until you choose.
Strictly necessary
Login, session, security and load-balancing cookies. Without these the site does not work.
Analytics
Google Analytics 4 (page views, time on page, source attribution). Aggregated only, never sold.
Advertising
Google AdSense and ad measurement tags. Without this category, ads are non-personalised (cookieless).
Personalisation
Remember preferences such as theme, language, and reading position so they persist between visits.