Blacklist Check
Is your domain or mail-server IP on a spam blocklist? Enter a domain (we’ll check it and its mail servers) or an IPv4 address to see whether it’s listed on major DNSBLs like Spamhaus and SpamCop — with the return codes and how to get delisted.
What is a blacklist (DNSBL)?
A DNS-based blocklist (DNSBL, also called an RBL or “blacklist”) is a live list of IP addresses and domains known for sending spam. Receiving mail servers query these lists in real time and reject or spam-folder mail from anything listed. Being on one — even by mistake or because you share an IP range with a spammer — can quietly wreck your deliverability.
How to get delisted
First fix the cause: a compromised mailbox, an open relay, a misconfigured server, or poor sending practice (buying lists, high complaint rates). Then use the delisting/removal form on the specific list’s site. Tighten your sending authentication first — check SPF, DKIM and DMARC and set a reverse DNS (PTR) record for your sending IP.
Authoritative coverage (Spamhaus)
The most-used lists (Spamhaus) block queries from public resolvers and reserve their free mirror for personal, non-commercial mail servers. The sanctioned way to query them programmatically is a free Spamhaus Data Query Service (DQS) account. Once its key is configured here, this tool checks Spamhaus ZEN (IP) and DBL (domain) too.
Frequently asked questions
▸ ▾ Why is my IP blacklisted when I didn't send spam?
Common causes: a compromised account or device on your network, sharing an IP range with a spammer (especially on shared hosting), an open relay, or a sudden spike in volume. Check for compromise, then request delisting.
▸ ▾ Does a clean result guarantee inbox placement?
No. Blocklists are one signal among many. Authentication (SPF/DKIM/DMARC), reputation, content and engagement all matter. A clean blocklist result removes one big blocker, not all of them.
▸ ▾ How often is the result updated?
Checks are live over DNS and cached here for up to an hour. After you fix a problem and request delisting, it can take from minutes to a few days for a list to clear.