Question 1

What is a mail blacklist (DNSBL)?

Accepted Answer

A DNS-based blocklist (DNSBL), also called an RBL, is a list of IP addresses known to send spam or be associated with malicious activity. Mail servers query these lists to decide whether to accept or reject incoming email. If your IP is listed, your emails may be blocked or sent to spam folders.

Question 2

Can I check a domain name as well as an IP address?

Accepted Answer

Yes. You can enter either an IPv4 address or a domain name. When you enter a domain, we resolve it to its IPv4 address and check that address against IP-based blocklists. We also check the domain itself against domain-based blocklists like Spamhaus DBL, SURBL, and URIBL.

Question 3

Which blocklists do you check?

Accepted Answer

We check 15 IP-based blocklists including Spamhaus ZEN, SpamCop, Barracuda, UCEPROTECT (Levels 1-3), SORBS, CBL, PSBL, SpamRATS, S5H, InterServer, and DroneBL. When you check a domain, we also query 10 domain-based blocklists including Spamhaus DBL, SURBL, URIBL, Spamhaus ZRD, and Spam Eating Monkey.

Question 4

What should I do if my IP is listed?

Accepted Answer

First, identify and fix the cause of the listing (compromised account, misconfigured mail server, open relay, etc.). Then visit the blocklist's website to request delisting. Most lists have an automated removal process once the underlying issue is resolved.

Question 5

Why are my emails going to spam?

Accepted Answer

Being listed on a blocklist is one of the most common reasons. Other causes include missing SPF, DKIM, or DMARC records, a poor sender reputation, or sending from a shared IP with other spammers. Use this tool to check your blacklist status, then use our SPF Validator and DNS Lookup tools to verify your email authentication records.

Question 6

How often are blocklists updated?

Accepted Answer

Each blocklist maintains its own update schedule. Some like Spamhaus and SpamCop update in real-time, while others update every few hours. If you've recently been delisted, it may take a short time for the change to propagate.

Question 7

Is this tool free?

Accepted Answer

Yes, this mail blacklist checker is completely free to use with no registration required. You can check as many IPs or domains as you need.

Mail Blacklist Checker

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