Domain Blocklist Status

Domain Blocklist Status queries six major reputation feeds in parallel and deducts points for each listing. The lists feed into mail server filtering (Spamhaus DBL, SURBL, URIBL, Barracuda, SpamCop), browser security warnings (Spamhaus, URLhaus), and security product blocking (URLhaus is operated by abuse.ch, used by many enterprise security tools). A listing on any of these has real-world impact: mail bounces, users see scary browser warnings, security products block your domain in corporate networks.

How the check works

Six DNSBL/HTTP queries fire in parallel against your domain. Each list has its own per-list weight; if your domain is listed, the weight is deducted from the 40-point base. Confidence scales down if more than half of queries error out (network or upstream issue rather than real cleanliness).

• Spamhaus DBL (weight 15): the most widely-used domain blocklist. Listed domains see mail rejection at major receivers and browser warnings.
• SURBL Multi (weight 10): aggregates multiple SURBL feeds; widely used by mail filters.
• URIBL Multi (weight 8): another aggregated feed; used by some mail filters and security products.
• Barracuda Domain (weight 7): used by Barracuda email security products and partner filters.
• SpamCop Domain (weight 5): community-driven; usually expires automatically once spam reports stop.
• URLhaus (weight 10): abuse.ch malware-distribution feed; listings indicate active malware hosting.

Score = (40 - sum of per-list weights for listings) / 40, multiplied by confidence. Verdict thresholds via the standard CT composite mapping.

How the verdict maps to evidence

• Pass: clean on all six lists.
• Warn: listing on a low-weight list (SpamCop) or a single moderate-weight listing (URIBL, Barracuda).
• Fail: listing on a critical-weight list (Spamhaus DBL, SURBL, URLhaus) or multiple stacked listings.

Evidence shows blocklist_results per list (status, response_address, weight), spamhaus_dbl_summary if listed, queries_successful vs queries_total, confidence_multiplier, and any inconclusive_queries with the reason.

Fix: investigate root cause, then request removal

Every blocklist has its own removal process and most require you to address the underlying issue (compromise, abuse, misuse) before removal. Removing the symptom without fixing the cause typically results in re-listing within days. Investigate first; remove second.

First: figure out why you got listed

• Compromise: a legitimate site was hacked and is hosting malware, phishing, or spam-redirector content. Audit recent file changes, scan for webshells, check user accounts for unauthorized access.
• Compromised hosting: a shared hosting provider's IP range got listed; your domain is collateral damage. Check whether the listing is at the IP or domain level.
• Phishing/abuse content: a subdomain or page was used in a phishing campaign (could be customer-uploaded content, an open redirect, or unauthorized use).
• Mass mail: someone (yourself, a marketing team, or a compromised account) sent a high volume of unwanted email from your domain.
• Stolen brand: an attacker is using your domain in a typosquatting campaign and got the typosquat listed; verify the listing is for your actual domain.
• Email forwarders/list servers: legacy mail rules forwarding spam through your domain can get you listed via the forwarded path.

Per-blocklist removal

Spamhaus DBL (weight 15, critical)

Visit https://check.spamhaus.org/ and look up your domain. Removal requires identifying the cause and demonstrating remediation. Spamhaus does not auto-remove; you submit a removal request after fixing the underlying issue. Listings often persist for weeks if the cause is not addressed.

SURBL (weight 10, critical)

Visit http://www.surbl.org/surbl-analysis. SURBL aggregates several lists; identify which one contains your domain. Each sub-list has its own removal process, generally via email after addressing the cause.

URIBL (weight 8)

Visit https://uribl.com/. URIBL provides a self-service lookup and removal request. Address the cause (typically your domain appearing in spam content) before requesting removal.

Barracuda Reputation (weight 7)

Submit a removal request at http://www.barracudacentral.org/lookups. Barracuda reviews and removes after verification.

SpamCop (weight 5)

SpamCop listings auto-expire once spam reports stop. The fastest fix is to identify and stop the source; the listing usually clears within 24-48 hours. No removal request needed.

URLhaus (weight 10, critical)

Run by abuse.ch. URLhaus listings indicate active malware hosting. Investigate immediately: check for unauthorized file uploads, injected scripts, redirects to malicious payloads. The listing comes off automatically once URLhaus rescans and finds the malware gone, but you must remove the malicious content first.

Verify the fix

• Spot-check each list. Spamhaus: dig +short yourdomain.dbl.spamhaus.org (no answer = not listed). Same pattern for SURBL: dig +short yourdomain.multi.surbl.org. Etc.
• MXToolbox blacklist check (https://mxtoolbox.com/blacklists.aspx) provides a single-page view across many lists.
• Send a test email to a Gmail account; check the headers for any spam-flag references to a blocklist.
• Re-run the RedScore lookup. The score recovers as listings clear; some lists update DNS-level immediately, others have caching delays.

Common pitfalls

• Removing the symptom without the cause. Spam-source IP rotated, malware deleted, but underlying compromise still active. Re-listing within days. Investigate the entry point first.
• Listing on a shared-hosting IP that you cannot control. The IP-level listing is in the IP Blocklist Status check, not this one. If your domain shows up here, it is your domain that is listed, not just your IP.
• Caching delays in the blocklist DNS responses. After delisting, some resolvers cache the old listing for hours. Wait at least 24 hours after a removal confirmation before assuming the score will move.
• Customer-uploaded content getting your domain listed. If your platform lets users upload content under subdomains, abusive uploads can list your whole domain. Implement upload scanning and content moderation.
• Marketing automation that ignores opt-outs. Persistent unsolicited mail from your domain leads to SpamCop listings even when there is no "compromise". Audit your marketing tools' opt-out handling.
• Confusing domain blocklist with email reputation tools. Sender Score (Validity), Talos Reputation, and similar tools are not in this check. They use overlapping but distinct data; address the underlying behavior.