What does an email blacklist check do?
Blacklists (also called DNSBLs or RBLs) are databases of IP addresses that have been caught sending spam. Receiving mail servers query them on every incoming connection. If your mail server's IP is on one of these lists, the email you send gets rejected or dropped straight into the spam folder. Usually you're not the first to notice. A customer telling you "your email never arrived" is.
This tool checks the IP you enter (or resolves your domain to an IP first) against these lists: Spamhaus ZEN, SpamCop, DroneBL, PSBL, UBL and UCEPROTECT Level 1.
What do the results mean?
| Result | Meaning | What to do |
|---|---|---|
| Clean | The IP isn't on this list. | Nothing to do. If delivery problems continue, check your SPF, DKIM and DMARC records. |
| Listed | The IP is on this list, so receiving servers may reject your mail. | Find and stop the source of the spam first, then follow the list's removal (delisting) process. |
| Couldn't check | The list didn't answer the query or a query limit was hit. | Try again in a few minutes, or check directly on the list's own website. |
Why does an IP get blacklisted?
- A compromised email account: an attacker steals a user's password and sends thousands of spam messages through it. This is the most common cause.
- A malware-infected computer: a device behind the same outbound IP has turned into a spam bot.
- An open relay or weak SMTP settings: the server lets others send mail without authenticating.
- Unsolicited bulk sending: campaigns sent to purchased lists hit spam traps.
- A shared IP: another customer sending from the same IP drags your reputation down too.
How do you get off a blacklist?
Every list has its own rules. Some clear automatically once the source stops, others require a removal request. Our email blacklist removal guide covers the process step by step. In short:
- Find and stop the source: reset compromised passwords, clean infected machines, close any open relay.
- Confirm the spam has actually stopped by checking your outgoing mail queue and logs.
- Follow each list's delisting process. SpamCop and UCEPROTECT Level 1 expire on their own; Spamhaus has a lookup and removal form at check.spamhaus.org.
- Run this check again to confirm you're clean.
Blacklisting often goes hand in hand with missing email authentication. Check your domain's SPF, DKIM and DMARC records too, and read why emails go to spam.
Frequently asked questions
Can I enter a domain name instead of an IP?
Yes. If you enter a domain, the tool first resolves it to an IP address and checks that IP. If your mail is sent from a different server than your website, enter the mail server's IP or hostname directly (for example mail.yourcompany.com).
How long does it take to get off a blacklist?
It depends on the list. Automated lists such as SpamCop usually clear on their own within 24 hours once the spam stops. Manually reviewed lists such as the Spamhaus SBL can take several days. A UCEPROTECT Level 1 listing expires automatically after 7 days if no new spam is seen.
Why can the Spamhaus result differ?
Spamhaus limits anonymous DNS queries coming from large cloud and public DNS providers. For a definitive answer, also check at check.spamhaus.org.
Does being blacklisted affect my incoming email?
No. Blacklists only affect the email you send. Protecting your inbox from spam and phishing is a separate job, and that's what Spambil does.
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