How to Check if Your Domain or IP Is Blacklisted and Get Delisted

To check if your domain or IP is blacklisted, take the sending IP from a bounce or email header and look it up, along with your domain, at check.spamhaus.org. Then run a multi-list checker, such as our free Blacklist Checker, to sweep other common lists. If you are listed, fix the cause (a hacked account, a dirty list, a misconfigured server) before requesting removal, which is free on every reputable list.

The rest of this guide covers how to find the right IP, what a listing actually means, which lists matter, how delisting works for Spamhaus, Microsoft, Barracuda and SpamCop, and how to stop it happening again.

What is an email blacklist (blocklist)?

A blocklist, often called a DNSBL or RBL, is a database of IP addresses or domains that have been seen sending spam, being compromised or behaving badly. Mail servers query these lists in real time when a message arrives. If the connecting IP, or a domain in the message, is on a list the receiver trusts, the message may be rejected, delayed or sent to junk.

There are two kinds to keep apart:

• IP blocklists list the server that sent the mail. If you use Google Workspace, Microsoft 365 or a big email service provider, you usually share IPs with many other customers.
• Domain blocklists (such as the Spamhaus DBL) list domains that appear in the message, including links in the body. A listed domain can hurt you even if your sending IP is clean.

What does it mean if my domain or IP is blacklisted?

A listing means one list operator has decided that mail from that IP, or messages containing that domain, carry a spam risk. It is not a legal finding or a block by "the internet". What happens next depends on which receivers use that list:

• Bounces. Some servers reject the message outright and the bounce names the list, which is the clearest sign a listing is hurting you.
• Spam folder placement. Others use lists as one signal among many, so your mail still arrives but lands in junk more often.
• No visible effect. A listing on a small or rarely used list may change nothing, because few big mailbox providers consult it.

A listing is also a symptom. Something sent mail that looked like spam, or the IP sits in a range a list treats as risky. Our guide to how email blacklists work explains the DNS lookups and return codes behind this.

How do I find out if I'm blacklisted?

1. Find the right IP. Open a message you sent (or a bounce) and look at the full headers. In Gmail use Show original; in Outlook open the message and use File > Properties. The first Received: line added by an outside server shows the IP that connected. For website contact forms and newsletters, that might be your web host or email platform, not your mailbox provider.
2. Read the bounce. Many rejections name the list directly, for example "blocked using zen.spamhaus.org" or a Microsoft code such as 550 5.7.606-649 Access denied, banned sending IP.
3. Check Spamhaus first. Spamhaus's free IP and Domain Reputation Checker at check.spamhaus.org searches IPv4, IPv6 and domain names from one box and explains why a listing exists.
4. Run a multi-list checker. Our Blacklist Checker finds your domain's mail servers from its MX records, plus your website's IP, and looks up each IPv4 address on seven free blocklists, including SpamCop, PSBL, UCEPROTECT and Mailspike. It links to Spamhaus rather than querying it, because Spamhaus's terms require a paid data feed for services like ours. Your MX servers receive mail, and outgoing mail may leave from a different IP, so check the sending IP from step 1 too. Other free tools such as MXToolbox's blacklist check or MultiRBL query dozens of lists. Treat any of them as a sweep, not a verdict (see below).
5. Check your domain, not just your IP. Look up your domain and any link-shortener or tracking domains your newsletters use.

Make It Flow does not monitor blocklists continuously, but it does catch the setup problems that often lead to them. The free Email Deliverability Checker tests your MX, SPF, DKIM, DMARC, MTA-STS and BIMI records in one go, with copy-paste fixes for anything missing.

Which blacklists actually matter?

There are well over a hundred public lists, and many have little influence. Focus on the ones big receivers use.

Spamhaus says delisting is free. Any list or service that asks you to pay for "express" removal is not one you need to worry about; major receivers rarely rely on pay-to-delist lists.

Why does one checker say I'm listed when another says I'm not?

Multi-list tools query lists of very different quality, and some lists include whole hosting ranges by design. A few also give false results when the checking tool queries them through a large public DNS resolver, which Spamhaus restricts. If a result looks odd, confirm it on the list operator's own site before acting.

How do I get removed from a blacklist?

Removal requests only work once the problem has stopped. If spam keeps flowing, you will be relisted, sometimes with self-service removal switched off.

1. Find the cause. Common culprits: a compromised mailbox or WordPress site sending spam, malware on an office PC behind a shared IP, a contact form abused by bots, a purchased or old list hitting spam traps, or a server with no reverse DNS.
2. Fix it. Reset passwords and turn on multi-factor authentication, patch or clean the site, add CAPTCHA to forms, remove unengaged and bounced addresses. Our guide to signs your website was hacked helps if you suspect a breach.
3. Request removal on the list's own site.
   • Spamhaus: Use check.spamhaus.org. SBL listings must go through your ISP or host, and no other Spamhaus removal can proceed until the IP is off the SBL.
   • Microsoft: For 5.7.606-649, use the Office 365 Anti-Spam IP Delist Portal at sender.office.com, one email address and one IP per visit. Microsoft says it may take up to 24 hours or longer. For 5.7.511, email delist@microsoft.com with the full NDR and IP; Microsoft says it will reply within 48 hours.
   • Barracuda: Submit the removal form once with a valid explanation. Duplicate requests are ignored.
   • SpamCop: No request needed. The IP drops off 24 hours after the last report, and SpamCop asks people not to write in for early delisting.
4. Retest after a day. Check again and send a test to Gmail and Outlook.com addresses.

What if I'm on shared IPs from Google, Microsoft or an email platform?

If your mail goes through Google Workspace, Microsoft 365, Mailchimp, Brevo or similar, the sending IPs belong to them. You can't delist those yourself, and big providers manage their own reputations closely. Raise a ticket with the provider, include the bounce, and check your own domain reputation and authentication in the meantime. Problems on shared infrastructure more often come down to your domain: weak authentication or high complaint rates. Our guide on why emails go to spam covers those.

How do I stop getting blacklisted again?

• Authenticate everything. Publish SPF, sign with DKIM and add a DMARC record. The free SPF checker, DKIM checker and DMARC checker confirm each record is valid, or run the Email Deliverability Checker to test them all together.
• Set reverse DNS on any server you run yourself. Gmail requires a PTR record whose hostname resolves back to the same IP.
• Only mail people who opted in, and remove hard bounces straight away.
• Watch your complaint rate. Google asks senders to stay below 0.3% and recommends below 0.1%.
• Lock down forms and accounts. Most small-business listings start with a compromised login or an abused form.
• Check regularly. Free blocklist monitoring services and your email platform's alerts can warn you early, and a monthly run of the Blacklist Checker costs nothing. Make It Flow's paid plans also re-scan your DNS and email records on a schedule, which catches authentication changes, though not blocklist listings themselves.

Frequently asked questions

How do I check if my domain is blacklisted for free?

Look up your domain and sending IP at check.spamhaus.org, then run a free multi-list tool such as our Blacklist Checker. If a bounce message names a list, check that list's own website as well, since it has the final say on whether you are listed.

How long does it take to get off a blacklist?

It depends on the list. SpamCop expires 24 hours after the last report, Barracuda usually processes requests within 12 hours, and Microsoft says delisting can take 24 hours or longer. Spamhaus self-service removals for XBL and CSS are often quick once the cause has stopped, but SBL cases depend on your ISP.

Will being on one blacklist stop all my email?

Not usually. Each receiver chooses which lists it uses. A Spamhaus or Microsoft listing can block a lot of mail; a minor list might affect almost nobody. Check bounces to see which receivers are actually refusing you.

My home IP is on the Spamhaus PBL. Is that a problem?

No. The PBL lists ranges that ISPs say shouldn't send mail directly, which includes most home broadband. Your email client sends through your provider's server, not your home IP, so the listing has no effect unless you run your own mail server.

Can a domain be blacklisted even if my IP is clean?

Yes. Domain blocklists such as the Spamhaus DBL look at domains in the From address and in links. A compromised website, a spammy link shortener or a new domain used for aggressive mailing can all be listed.

Is my website blacklisted, or just my email?

They are different things. Email blocklists affect whether your messages are delivered. A website can separately be flagged by browser warning systems such as Google Safe Browsing, usually after malware or phishing pages appear on a hacked site. Check that with Google's Safe Browsing site status page and the Security issues report in Search Console.

Should I pay a service to remove me from blacklists?

No. Reputable lists don't charge for removal, and paid "delisting services" can't do anything you can't do yourself through the list's own form. Spend the effort on fixing the cause instead.

What to do next

Look up your sending IP and domain at check.spamhaus.org today, even if mail seems fine, and note which IPs your website, CRM and newsletter tool use. If you find a listing, fix the cause first, then request removal on the list operator's own site. Finally, tighten your authentication with our email authentication checklist so receivers have every reason to trust you.

Related reading

• How Email Blacklists Work: DNSBL Lookups, IP and Domain Lists: How DNS blocklists work, which IP or domain to check, what return codes like 127.0.0.2 mean, and why shared hosting IPs get listed when you did nothing wrong.

Sources

• Spamhaus: Goodbye Blocklist Removal Center, hello IP and Domain Reputation Checker
• Microsoft Learn: Remove yourself from the blocked senders list and address 5.7.511 errors
• Barracuda Central: Removal request
• SpamCop FAQ: How do I get my IP delisted?
• Google Workspace Admin Help: Email sender guidelines
• Google Transparency Report: Safe Browsing site status