Email blacklist (DNSBL) check
Check an IP address — or a domain's mail servers — against DNS blacklists, live in your browser over DNS-over-HTTPS. A list is marked listed or not-listed only when it actually gives a clear answer; the big ones a browser can't check (like Spamhaus) are labelled honestly rather than guessed.
Checks an IP (or a domain's mail servers) against 11 DNS blacklists that answer reliably over public DNS — plus an honest note on the major lists that can't be checked from a browser. Runs over DNS-over-HTTPS; nothing is stored.
Queries run in your browser over DNS-over-HTTPS; we don't log what you check. A blacklisting applies to a sending IP, not a domain — being listed doesn't always mean mail is blocked, and being unlisted here doesn't guarantee inbox placement. Delisting is done at each list's own site.
What an email blacklist check tells you
DNS blacklist (DNSBL)
A DNSBL is a list of IP addresses known for spam or abuse, published over DNS. Mail servers check a sender's IP against these lists before accepting a message; a listing can cause mail to be rejected or filtered to spam.
127.0.0.x answer means the IP is listed; NXDOMAIN means it
isn't. Here's what each status here means.
- Listed
- The blacklist published a 127.0.0.x record for this IP — it's on the list. The exact code often encodes why (spam trap, proxy, poor reputation); we show the code and its meaning where the list documents one.
- Not listed
- The list returned NXDOMAIN — no record for this IP, so it isn't on that list right now. This is the clean result.
- Can't verify
- The list refused our public resolver (a 127.255.255.x sentinel, SERVFAIL, or REFUSED). That's not a listed-or-not answer, so we report it honestly instead of guessing — and point you at the list's own lookup.
The honest part: why some lists show "can't verify"
Most free blacklist checkers query a long list of DNSBLs and paint each one green or red. The problem: several of the most important lists deliberately refuse queries from public resolvers like Cloudflare and Google — the only resolvers a browser can reach. When that happens they don't return your real status; they return a refusal.
We also leave out lists that have shut down — SORBS, offline since 2024, still answers
NXDOMAIN for everything, which a careless tool would show as a reassuring "not listed" on
a list that no longer exists. The result: the lists we mark green or red are ones we verified actually
answer truthfully over public DNS, and everything else is labelled for what it is.
How the check works
Enter an IPv4 address and we check it directly. Enter a domain and we first resolve its mail servers over DoH — its MX records, then each mail host's A record — because a blacklisting attaches to the sending IP, not the domain name. Each IP is then queried against every list by looking up its reversed form under the list's zone, exactly as a receiving mail server would. All of it runs from your browser straight to public DoH resolvers, so we never see or store what you check.
If you're listed — and what a clean result doesn't prove
A listing means abuse was seen from that IP: a compromised device, an open relay or proxy, a misconfigured server, or genuine spam. Fix the cause first — a delisting won't hold if the behaviour continues. Then use the removal process on that specific list's site; many lists auto-expire once the problem stops, while others need a manual request. Weigh listings by which list: a major, widely-trusted list has real delivery impact, while an aggressive or niche one may affect almost nothing.
And a clean result here is necessary but not sufficient. Reaching the inbox also depends on SPF, DKIM, and DMARC authentication, your domain and IP reputation, recipient engagement, and each provider's content filtering — none of which an IP blacklist can see. Not being listed clears one hurdle; it doesn't guarantee delivery.
Email blacklist check — frequently asked questions
What is a DNS blacklist (DNSBL / RBL)?
A DNS blacklist — also called a DNSBL or RBL (Realtime Blackhole List) — is a list of IP addresses known for sending spam or abuse, published over DNS. A receiving mail server checks a sender's IP against these lists by looking up a specially-formed record; a 127.0.0.x answer means "listed", and NXDOMAIN means "not listed". Being on a widely-used list can cause your mail to be rejected or sent to spam.
Why can't you check Spamhaus (or SpamRATS) here?
Spamhaus and some other lists deliberately refuse queries that arrive through large public resolvers like Cloudflare or Google — the ones a browser can reach. Instead of your real status they return a refusal code (Spamhaus uses 127.255.255.254) over one resolver and NXDOMAIN over another. A naive checker reads those as "listed" and "not listed" respectively — both wrong. We detect the refusal and tell you to use the list's official lookup, rather than showing you a fabricated status. That honesty is the whole point of this tool.
My IP is listed — what do I do?
First find and fix the cause: a compromised device or account, an open relay or proxy, a misconfigured mail server, or a genuine spam problem on your network. Listings usually mean abuse was seen from your IP. Once the cause is fixed, use the delisting or removal process on that specific list's website (each list runs its own). Many lists auto-expire a listing after the bad behaviour stops; some require a manual removal request.
Does being on a blacklist mean my email is blocked?
Not necessarily. Every receiver decides how to use these lists — some reject outright, some add spam score, many ignore smaller lists entirely. A listing on a major, widely-trusted list (like Spamhaus) has real delivery impact; a listing on an aggressive or niche list may affect almost nothing. Judge by which list, not just whether you're listed somewhere.
I'm not listed here — does that mean my email will reach the inbox?
No. Not being on these IP blacklists is necessary but not sufficient. Inbox placement also depends on SPF, DKIM, and DMARC authentication, your domain and IP reputation, engagement signals, and each provider's content filtering — none of which a blacklist check can see. Use the DMARC & SPF checker to confirm your authentication is set up correctly.
What's the difference between an IP blacklist and a domain blacklist?
This tool checks IP-based blacklists — lists of sending IP addresses. Those are distinct from domain/URI blacklists (like SURBL or URIBL), which list domains that appear inside spam messages rather than sending IPs. An IP can be clean while a domain is listed, or vice-versa; they answer different questions.