Email Blacklist Checker: Free IP & Domain RBL Check

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Check whether a domain's mail servers or an IP address are listed on Spamhaus, Barracuda, SpamCop and other email blocklists, and see the reputation score.

Email Blacklist (DNSBL / RBL) Overview

What is an email blacklist?

An email blacklist is a public list of IP addresses or domains that have been seen sending spam. When a message arrives, the receiving mail server looks up the sender in these lists through DNS. If the address is listed, the message is often rejected or sent straight to spam, even when SPF, DKIM and DMARC all pass.

What does this checker look at?

For a domain, the checker finds its mail servers in the MX records and checks each IPv4 address against well known IP blocklists such as Spamhaus ZEN, Barracuda, SpamCop, UCEPROTECT, PSBL, Mailspike and DroneBL. It also checks the domain name itself on the domain blocklists Spamhaus DBL, SURBL and URIBL. You can enter a single IPv4 address instead to check only that address.

How is the reputation score worked out?

The score starts at 100. Each blocklist that lists you takes points away, with the most widely used lists counting the most. For mail servers, a missing reverse DNS name, or one that does not point back to the same address, also lowers the score. 90 and above is good, 60 to 89 is fair and anything lower is poor.

Why do servers get listed?

The usual causes are a hacked email account or website sending spam, an infected computer on the same network, a mail server open to relaying, or bulk mail sent to old or purchased lists that hit spam traps. On shared hosting, another customer on the same IP address can get the address listed too.

FAQs

An email blacklist, also called a DNSBL or RBL, is a public list of IP addresses or domains that have sent spam. Mail servers look up the sending address in these lists and reject or filter mail from anything that is listed.

For a domain it finds the mail servers in its MX records and checks their IPv4 addresses, and it checks the domain name itself on the domain blocklists. You can also enter a single IPv4 address to check only that address.

First stop the cause: a hacked account, an infected device, an open relay or a bad mailing list. Then use the removal link shown next to the listing. Some lists remove entries automatically after a quiet period, others need a request.

Many receivers distrust mail from servers whose IP address has no reverse DNS (PTR) name, or whose PTR name does not point back to the same IP. Ask your hosting provider to set a PTR record that matches your mail server name.

No. Being on no blacklist removes one common reason for rejection, but delivery also depends on SPF, DKIM and DMARC, your sending history and the content of your messages.

Blacklist Troubleshooting & Practical Fixes

Spamhaus is used by most large mail providers, so a listing there causes the most bounces. The listing reason tells you which Spamhaus list caught the address.

How to fix: Find and stop the source of the spam first: change passwords of compromised accounts, clean infected machines and close any open relay. Then open the removal link shown in the result and follow the steps for that listing.

Some lists are strict or list whole network ranges, so a single listing on a minor list may affect only a few receivers.

How to fix: Read the reason on the list's own page. Many small lists remove entries automatically after a quiet period. If the whole range of your hosting provider is listed, ask the provider to deal with it or to give you a cleaner address.

Receivers expect a mail server's IP address to have a PTR name that points back to the same address. Without it, mail is often scored as spam.

How to fix: Ask the company that owns the IP address (your hosting or cloud provider) to set a PTR record such as mail.yourdomain.com, and make sure that name has an A record pointing back to the same IP.