Free Spamhaus blacklist checker
Check if your sending domain is on the Spamhaus DBL or SURBL in seconds — with what a listing means and how to get delisted. No signup.
What this checker looks at
It checks your domain against the two reputation lists that matter most for a sending domain: the Spamhaus DBL (Domain Block List) and SURBL, which lists domains found inside spam messages. A listing on either can silently send every campaign on the domain to the spam folder.
Domain lists vs IP lists
Spamhaus runs more than one list. The DBL lists domains — the part you own and can fix. The SBL, XBL, and PBL list IP addresses, and if you send through Instantly or Smartlead, that IP belongs to your provider's shared pool, so those are usually theirs to resolve, not yours. The Spamhaus SBL, XBL, PBL explainer breaks down which is which.
The truth table: listed vs refused
Blacklists answer DNS queries with 127.x.x.x codes. Some codes mean a domain is listed. Others mean the list refused to answer— Spamhaus and SURBL both block queries from shared and datacenter resolvers, which is exactly where most SaaS checkers run. A tool that can't tell the two apart invents listings that don't exist, or shows clean for a domain nobody checked.
| Answer | Meaning |
|---|---|
| 127.0.1.2 | Spamhaus DBL — listed as a spam domain |
| 127.0.1.4–.6 | Spamhaus DBL — phishing, malware or botnet listing |
| 127.0.0.64 | SURBL — abuse bit (bits add up: 72 means abuse + phishing) |
| 127.0.0.1 | SURBL — your access is blocked. Not a listing |
| 127.0.1.255 | Spamhaus DBL — query not authorized. Not a listing |
| 127.255.255.x | Spamhaus — query blocked (public or datacenter resolver, no key, volume). Not a listing |
| timeout / SERVFAIL | No answer at all — not clean, not listed |
This checker reads every one of those refusal codes as "couldn't check" — never as listed, never as clean. A blacklist check has three honest outcomes, not two.
Test any checker in 60 seconds
Both lists publish permanent test entries. Run these two lookups from the same network your checker uses:
nslookup dbltest.com.dbl.spamhaus.orgExpected: 127.0.1.2 (a permanent test entry). Getting 127.255.255.x means your resolver is refused — a checker on this path can't see real listings.
nslookup test.surbl.org.multi.surbl.orgExpected: a 127.0.0.x listing bit. Getting 127.0.0.1 means SURBL blocked you — anything that checker reports is a guess.
If your domain is listed
Don't start with the removal form. Pause sending, fix the root cause (almost always a purchased or unverified list, or a spam-trap hit), then request delisting and re-warm slowly — the full order is in the guide to fixing a blacklisted domain. Want the whole deliverability picture, not just blacklists? The deliverability checker adds SPF, DKIM, DMARC, MX, and domain age.