Free Blocklist Checker

Check if your IP address or domain is listed on any DNSBL/RBL blocklist.

Supports IPv4 addresses and domain names

What are email blocklists?

DNS-based Blackhole Lists (DNSBL) and Real-time Blackhole Lists (RBL) are databases of IP addresses and domains known to send spam. Mail servers query these lists to decide whether to accept incoming emails.

Being listed on a major blocklist like Spamhaus or Barracuda can severely impact your email deliverability, causing emails to bounce or land in spam folders.

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IP blocklists

Check your sending server's IP address against major DNSBL providers.

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Domain blocklists

Domain-based lists (URIBL, SURBL, DBL) check your domain name in email content.

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Delisting

Fix the issue causing the listing, then request removal from each blocklist provider.

Frequently Asked Questions

A DNSBL (DNS-based Blackhole List) or RBL is a list of IP addresses or domains known to send spam. Mail servers check these lists to decide whether to accept, reject, or flag incoming emails.
Each blocklist has its own delisting process, usually a self-service form. First fix the underlying issue (compromised server, spam complaints), then request removal.
Spamhaus (ZEN, DBL) is the most impactful. Barracuda, SpamCop, and SORBS are also widely used. Being listed on any of these significantly affects deliverability.
Yes. Enter an IPv4 address for IP blocklists or a domain name for domain blocklists. The tool automatically detects the input type and queries the appropriate list.
Common reasons: sending spam, compromised server, high bounce/complaint rates, open relay, shared IP with a spammer, or botnet activity.

Go beyond blocklists

Blocklists are just one factor. Run a full audit to check SPF, DKIM, DMARC, TLS, IP reputation, and more.

Run free full audit

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