Domain Blacklist Checker — Spamhaus DBL, URIBL & ZRD

IP blocklists query reversed IPv4 octets — they answer whether an address sent spam or hosted abuse. Domain blocklists query the hostname string itself — they answer whether a domain appeared in spam URLs, phishing kits, or newly registered domain campaigns regardless of which IP currently hosts it.

Our note field reminds operators to check both dimensions. Marketing teams rotating landing pages through clean CDNs still get DBL listings when domains appear in spam templates. Conversely, a clean DBL result does not guarantee the resolved IP is clean on zen or XBL.

Spamhaus Domain Block List covers domains found in spam messages and malicious email campaigns. Listings often follow honeypot spam traps and community reports. DBL hits block mail containing those domains in body links, headers, or redirect targets depending on receiver configuration.

Delisting requires demonstrating the domain is no longer used maliciously and resolving any compromise that led to spam appearance. DBL is among the most impactful domain lists for email receivers worldwide.

URIBL publishes domain lists used by mail filters to score URI reputation in message bodies. multi.uribl.com aggregates URIBL feeds into a single query point. A listing indicates the domain appeared in URIBL's threat corpus — often overlapping with spam and phishing URL campaigns.

URIBL maintains separate commercial and free tier policies. Our query uses the multi zone consistent with common mail server configurations. Document URIBL hits when requesting removal through URIBL's published procedures.

Zero Reputation Domains list flags newly registered or previously dormant domains that lack established sending reputation. ZRD is not an accusation of malice — it warns receivers that the domain is young. Legitimate product launches sometimes hit ZRD until age and clean sending history accumulate.

If your startup domain lists on ZRD only, factor domain age into remediation. Warm up mail gradually, publish SPF and DMARC, and retest after the registration age window passes. Pair with domain reputation checker for WHOIS age context.

Run before email campaigns using new tracking domains, after acquiring domains from marketplace transfers, when link shorteners redirect through your hostname and users report blocks, and during phishing incident response on lookalike domains targeting your brand.

Security teams monitoring typosquatting portfolios batch-check acquired defensive domains to ensure previous owner abuse does not inherit to your organization.

Enter the exact hostname appearing in spam URLs or certificates. DBL queries the label you submit — phishing.example.com and example.com are distinct DBL keys. Deep subdomain chains in phishing often use dedicated labels worth checking individually.

Wildcard DNS does not automatically propagate DBL status — each published hostname in spam is listed separately when reported.

Domain reputation checker combines WHOIS age, SPF, DMARC, and DNSBL into a numeric score. Domain blacklist checker focuses exclusively on DBL, URIBL, and ZRD listing status without authentication or age heuristics.

Use blacklist checker for definitive DNSBL answers. Use reputation checker for holistic trust scoring when onboarding vendor domains.

Mail security gateways often query domain DNSBLs at SMTP time and again at URL extraction time. Web proxies and secure web gateways query domain lists for outbound click protection. A DBL hit can block mail even when SPF passes if body links trigger filters.

Combine with malware URL scanner when investigating specific URLs rather than bare domain labels — URL scanners analyze path and query parameters DBL ignores.

Each list maintainer publishes distinct removal workflows. Spamhaus DBL and ZRD use Spamhaus removal portals. URIBL follows URIBL policy pages. Provide evidence of remediation, not just removal requests.

After delisting, TTL and resolver caching delay clean propagation. Retest periodically until all three zones report clean consistently.

Domain DNSBL queries use public DNS for names you submit. Query only domains you own or are authorized to investigate. Listing a competitor's domain without cause may violate acceptable use policies.

Results are informational signals for security and mail operations — not legal findings of fraud.