Is Your Domain or IP Address
Blacklisted for Spam?

Yes, it's completely free. No account, no login, and no limit on how many times you can use it. We never publish the domains or IPs you check in any public list, either.

For diagnosing delivery problems, check both — the sending server's IP address and the domain after the @ in the sender's address are tracked by separate sets of lists.

For a pre-purchase check on an expired domain, the domain name is enough. Right after signing up for a new server or VPS, checking the IP address is enough.

It depends on which list. If it's a major one like Spamhaus, SpamCop, Barracuda, or SORBS, act right away — it really is affecting your email delivery.

If it's only an obscure, small-scale list, very few mail servers actually consult it, so real-world impact is typically minimal.

We're querying several hundred lists, so it typically takes 10–60 seconds to finish — sometimes longer depending on network conditions. Please keep the page open and wait.

Nothing's broken. Many DNSBLs rate-limit free high-volume queries and don't respond when busy, and some listed services are no longer actively maintained. You can treat "No Response" essentially the same as "Not Listed."

Yes. Any IDN you enter (e.g. accented or non-Latin characters) is automatically converted to Punycode (the "xn--" form) before we run the check.

Being on a DNSBL is one possible cause, but Gmail also applies its own reputation criteria on top of that. If this tool shows "Not Listed," work through your SPF/DKIM/DMARC setup, reverse DNS for your sending IP, and your sending frequency and content next.

You can also check domain-level deliverability with Google's Postmaster Tools.

Yes — results are cached on our server for 30 days, and each result page has its own shareable URL you can revisit or send to others anytime. You can also use the "Copy Results" button to save them as plain text.

DNSBLs are an email-focused mechanism and don't directly determine search rankings. That said, a domain that shows up on a DNSBL was very likely used for spam or phishing in the past, and that history is itself a major risk for anyone repurposing an aged domain — making this a genuinely useful signal to check before you buy.