UptimeTea
Free tool, no signup

Domain and IP blacklist checker
Is your mail landing in spam because of a blocklist?

Look a domain or an IPv4 address up in Spamhaus, Barracuda, SpamCop and SURBL at the same time. See which lists flag it and where to request removal.

Check a domain or IP

Lookups are ordinary DNS queries. Nothing is stored, and results are cached for five minutes.

How DNS blacklists work

A lookup, not a download

To check 203.0.113.7 against a list, a mail server looks up 7.113.0.203.zen.spamhaus.org. No answer means clean. An answer in 127.0.0.x means listed, and the last number says why.

IP lists and domain lists

IP lists flag the servers that send mail. Domain lists flag names that appear in spam, such as the links in a message body. A clean domain on a listed server still gets blocked.

Listings come from traps

Lists run spam traps: addresses nobody would ever write to. Mail that reaches them is unsolicited by definition. A burst of it from your IP is enough to get listed.

Most listings expire

Many lists drop an entry automatically once the spam stops. Others need a removal request. Either way, fix the cause first, or the listing comes straight back.

Getting off a blacklist

  1. 1

    Find the source

    Check mail logs for a compromised account, a hacked plugin or a contact form sending to arbitrary addresses.

  2. 2

    Stop the spam

    Reset passwords, patch or remove the vulnerable code, and close any open relay.

  3. 3

    Request removal

    Use the delisting link for each list that flags you. Explain what you fixed.

  4. 4

    Check again here

    Run this checker after a few hours. Lists update on their own schedules.

  5. 5

    Separate web and mail

    Send mail through a dedicated provider, so a problem on the web server never takes email down with it.

Frequently asked questions

What is a DNS blacklist?
A DNS blacklist (DNSBL) is a list of IP addresses or domains seen sending spam or hosting abuse, published through DNS so any mail server can query it in milliseconds. Mail servers check incoming connections against a few of them and reject or junk mail from anything listed.
Which blacklists does this tool check?
For an IP address: Spamhaus ZEN, Barracuda and SpamCop, the three most widely used IP lists. For a domain: the Spamhaus Domain Block List and SURBL, plus the three IP lists for every address the domain's A record points to.
What does "unknown" mean?
The list did not give a usable answer within 3 seconds, or it refused the query. Spamhaus refuses lookups relayed through large public resolvers and answers with a special code instead. Unknown is not a listing. Try again in a few minutes.
My IP is listed. How do I get it removed?
Fix the cause first: a compromised account, an open relay, a form that sends mail to any address. Then follow the delisting link next to the list. Some lists, such as SpamCop, expire listings on their own within a day or two once the spam stops.
Why is my domain clean but its IP listed?
Shared hosting. Your site shares a server, and its IP, with other customers. If one of them sends spam, the address gets listed for everyone. Ask your host to fix it, or send mail through a dedicated provider instead of the web server.
Can I be told when my domain is blacklisted?
Not yet from this page. UptimeTea monitors uptime, SSL certificates, DNS and domain expiry on the free plan, so you hear about the other ways a site breaks before your customers do.

Explore more

DNS propagation checker

Moved mail to a new provider? Check the MX record has reached every resolver.

SSL certificate checker

See whether a certificate is valid, trusted and how long until it expires.

Status pages

Tell customers about email delivery problems on a status page instead of in a support inbox.

For agencies

Watch every client site's uptime, SSL and DNS from one dashboard.

A blocklist is one way a site breaks.

Downtime, an expired certificate, a DNS change and a lapsed domain are the others. UptimeTea watches all four and alerts you first. Free plan, 50 monitors, no credit card.