Spamhaus Lookup — zen, SBL, XBL & PBL DNSBL Check

Spamhaus publishes several DNSBL zones for different abuse categories. SBL — Spamhaus Block List — covers verified spam sources and spam operations. XBL — Exploits Block List — aggregates hijacked hosts, worms, and exploit-driven spam sources including CBL and composite feeds. PBL — Policy Block List — covers end-user IP ranges that should not deliver mail directly to the internet without provider SMTP relays.

zen.spamhaus.org combines SBL, XBL, and PBL into one query for mail servers that prefer a single check. Our tool queries zen plus each constituent zone separately so you see both the combined answer and which specific list contributed when multiple zones return listings.

listedZones collects human-readable labels for zones that returned positive at query time. SBL hits often trace to spam campaigns or compromised marketing infrastructure. XBL hits suggest exploit activity, open proxies, or malware-driven mail. PBL hits frequently mean a residential or dynamic IP attempted direct SMTP delivery against policy — common when home users misconfigure mail clients.

Multiple zone hits compound severity in abuse scoring even though each zone has independent delisting procedures. Document which zones listed in tickets when contacting hosting providers or ISPs.

DNSBL queries reverse IPv4 octets and append the zone hostname — 192.0.2.10 becomes 10.2.0.192.zen.spamhaus.org. A positive DNS A record answer indicates listing; NXDOMAIN typically means not listed for that zone. Our implementation queries through Google Public DNS for consistency with other live lookup tools in this suite.

Results include the exact query string per zone in the results array for reproducibility when opening Spamhaus removal requests or correlating with dig output in terminal troubleshooting.

When you enter a domain, we resolve the current A record IPv4 and run Spamhaus checks against that address. Mail deliverability problems tied to web hosting IPs require checking the SMTP egress IP separately — web and mail often use different addresses on the same domain.

resolvedFrom preserves the original hostname in results for audit trails. CDN-proxied domains resolve to edge anycast IPs that may carry unrelated neighbor listings.

If zen lists but you need delisting granularity, read individual SBL, XBL, and PBL results. zen positive with SBL positive and XBL clean suggests spam-specific listing. zen positive with only PBL positive often indicates policy block rather than malware compromise.

Some mail platforms query only zen for performance. Our per-zone breakdown saves time when Spamhaus lookup pages ask which list type applies to your removal case.

Spamhaus requires fixing underlying abuse before removal from SBL and XBL. PBL removals may involve using provider SMTP relays or requesting ISP range exceptions. Our note field reminds that 127.255.255.254 style responses indicate listing per Spamhaus documentation.

We do not submit delisting requests on your behalf. Use official Spamhaus removal portals and include evidence of remediation. Retest with this tool after propagation delays.

Our general blacklist checker queries multiple DNSBL publishers beyond Spamhaus — SpamCop, Barracuda, UCEPROTECT, and others. Spamhaus lookup focuses exclusively on Spamhaus zones with labeled SBL XBL PBL breakdown.

Run both during mail deliverability audits. Non-Spamhaus listings won't appear here; Spamhaus-specific detail won't appear as granularly in the general checker.

Mail administrators test new egress IPs before cutover, verify delisting after compromise recovery, and document blocklist status for ESP onboarding questionnaires. SOC teams correlate phishing campaign sending IPs with Spamhaus XBL hits for attribution notes.

Pair with PTR record lookup and email deliverability checker when diagnosing reverse DNS and authentication issues alongside blocklist status.

Spamhaus listings feed many commercial threat platforms. A positive result here often matches what partners see in aggregated feeds hours later. Export JSON for CMDB enrichment and ticket attachments.

Combine with threat intelligence lookup for composite domain or IP briefs that include Spamhaus alongside phishing heuristics and broader reputation scoring.

Spamhaus queries are logged by list operators per their policy. Use only for authorized mail infrastructure review and abuse triage on addresses you manage or investigate legitimately.

Listing status changes with remediation. A clean result today does not guarantee future cleanliness — schedule periodic rechecks on production mail egress.