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How to Check If Your IP Address Is Blacklisted (and How to Get Delisted)

Ekim 4, 2026 · IpDnsHub ·
email security blacklist

What Is an IP Blacklist?

Email blacklists — more precisely DNS-based blackhole lists (DNSBLs) — are databases of IP addresses that have sent spam or show signs of abuse. Mail servers check incoming connections against one or more of these lists and may reject, delay or filter mail from listed addresses.

You can check an address against common lists with our Spam Database Lookup.

How a DNSBL Lookup Works

DNSBLs are queried through ordinary DNS. To check 203.0.113.25 against a list at zen.spamhaus.org, the address is reversed and the list’s domain is appended:

25.113.0.203.zen.spamhaus.org

If the name does not exist, the address is not listed. If it returns an address in the 127.0.0.x range, it is listed, and the exact value usually tells you which sub-list caught it. Some lists return special codes when they refuse to answer — for example when queries come through large public resolvers — so an unexpected answer is not automatically a listing.

Signs That You Are Listed

  • Bounce messages that mention a list name, such as Spamhaus, Barracuda or SpamCop.
  • A sudden increase in messages going to spam for many different recipients.
  • Complaints from customers that your messages never arrived.

Common Causes

  • A compromised account or device: a stolen mailbox password or an infected computer sending spam through your server.
  • A vulnerable website: contact forms without protection and outdated plugins are often abused to send mail.
  • Bad list practices: sending to purchased or very old lists hits spam traps.
  • Shared or recycled addresses: on shared hosting or a newly assigned IP, the listing may be caused by another user or a previous owner.
  • Dynamic address ranges: some lists include all home and mobile address ranges on purpose, because legitimate mail servers should not send from them.

How to Get Delisted

  1. Find and fix the cause first. Change compromised passwords, scan devices, patch the website, stop sending to bad lists. Delisting without fixing the cause usually leads to a quick relisting.
  2. Check your mail server setup. Make sure you are not an open relay, that your PTR record is set, and that SPF, DKIM and DMARC are published.
  3. Use the list’s official removal page. Each list has its own process. Some remove addresses automatically after a period without new spam; others require a request.
  4. Be wary of paid “express delisting”. Reputable lists do not require payment for removal.
  5. Monitor afterwards. Check the address again over the following days.

Not All Lists Matter Equally

There are dozens of public lists. A few are used by many mail providers; others are rarely used. If you appear on an obscure list that no major provider uses, it may have little real effect. Focus first on lists named in your bounce messages.

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