suribs.org — free RHSBL

A free, keyless DNS blocklist (RHSBL), and a same-data web lookup. Severity-tiered results — the same dangerous / malicious / spam terminology MISUIC uses — plus safe for confirmed-good hosts and unknown for hosts observed but not confidently classified either way. No account or API key needed. Hostname-level, exact match only — a listing for evil.example.com never widens to cover example.com or other subdomains.

The RHSBL zone is delegated as a subdomain, z.suribs.org (not the bare suribs.org apex) — that delegation, and the rbldnsd service behind it, are being built out; treat the query format below as the reference for when it's live rather than assuming a live answer right now. For a working lookup today, use the free box on suribs.com's homepage, which serves this exact same confirmed view already.

How to query

Append the hostname you want to check to z.suribs.org and query for an A record, same convention as any RHSBL:

dig a evil.example.com.z.suribs.org
dig txt evil.example.com.z.suribs.org

A listed host answers with one of the addresses below plus a TXT record naming the tier. A host with no data either way answers NXDOMAIN — there is no bare "clean" response, matching standard RHSBL/DNSBL convention; a confirmed-clean host instead gets the explicit safe answer below.

Response codes

Address	Tier	Meaning
`127.0.0.2`	dangerous	Phishing or malware. No override — highest severity.
`127.0.0.4`	malicious	Advance-fee / lottery scam, or extortion.
`127.0.0.8`	spam	Low-grade promotional/click spam.
`127.0.0.16`	has full url encoding	Full URL percent-encoding obfuscation. Standalone — never combined with the tiers above.
`127.0.1.2`	unknown	Observed/scanned, no confident verdict either way. Distinct from no data at all (which NXDOMAINs).
`127.1.0.2`	safe	Confirmed good standing.

The tier terminology (dangerous/malicious/spam) matches MISUIC's own severity ratings — the two systems describe the same underlying evidence the same way, whether you're consuming SURIBS directly or seeing a MISUIC-flagged link.

Policy

This free zone's policy is fixed, not configurable: confirmed listings only (never unconfirmed), no per-requester allowlist. For a threshold you control, category-level filtering (not just tier), your own allowlist, and higher-volume/rate-limited access, see the licensed API and keyed RHSBL at suribs.net.

Prefer a web lookup?

The same confirmed-bad-only view is available as a simple web form, no DNS client needed, at suribs.com.