Email & IP Blacklist Checker — DNSBL Lookup Tool

About the blacklist check

Check whether an IP address or domain appears on well-known spam and abuse blocklists (DNSBL / RBL). A listing is a common reason why email bounces or goes to spam.

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What a listing means

Blocklists record addresses that sent spam or showed signs of infection. Receiving mail servers consult them and may reject or junk mail from a listed address.

Getting delisted

Find and fix the cause first: a compromised account, an open relay or a misconfigured sender. Then follow the list's removal process. Requesting removal before fixing the cause usually leads to a new listing.

Shared and dynamic addresses

Residential and dynamic IP ranges are listed by policy on some lists; this is not a sign of misuse. Send mail through your provider's relay instead.

What this tool does

Queries major DNS-based blackhole lists (DNSBLs) — including Spamhaus, Barracuda, and SpamCop — to check whether a given IP address is currently flagged as a spam or malware source. If you enter a domain instead of an IP, it's resolved to its mail-sending IP first.

Why this matters for email deliverability

Before troubleshooting why legitimate mail is landing in spam or being rejected outright, check whether the sending IP is blacklisted — receiving mail servers routinely consult these lists and will reject or quarantine mail from a listed source regardless of how well SPF, DKIM, and DMARC are configured.

What to do if you're listed

Each DNSBL operator has its own delisting process, usually a web form on their site — search for the zone name shown in the results plus "delisting" to find it. Getting listed again after removal usually means the underlying cause (an open relay, a compromised account, or a misconfigured server sending unsolicited mail) hasn't actually been fixed.

Frequently asked questions

I'm not listed, so why is my mail still going to spam?

Blacklisting is one of many spam signals — check the Email Health tool for SPF/DKIM/DMARC configuration issues too, since receivers weigh authentication as heavily as reputation.

How many blacklists does this check?

It queries several major DNSBLs in real time (including Spamhaus and Spamcop-style lists), not just one — a single tool call covers the lists mail providers actually check most often.

I'm listed on one obscure blacklist — how urgent is this?

Not very. A listing on Spamhaus or another major list can genuinely hurt deliverability; a listing on a small or rarely-used list usually has little practical effect. Prioritize fixing the major ones first.

How often are blocklists updated?

Continuously. Listings expire automatically on some lists after a period without abuse.

Is being on one list serious?

It depends on the list. A few widely used lists affect most receivers, while others are rarely consulted.

Can I check a domain as well as an IP?

Yes. Domain blocklists look at the domains used in message content and links.

Blacklist Check

Is this IP address on a spam blocklist?