Email Blacklist Checker
Check if an IP address or domain is listed on 15 major spam blacklists (DNSBLs)
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Frequently Asked Questions
An email blacklist (also called a DNSBL — DNS Blackhole List or DNS-based Blacklist) is a real-time database of IP addresses or domains known to send spam. Mail servers query these lists before accepting email. If the sending IP is listed, the message is rejected or marked as spam. Being listed on even one major blacklist can severely hurt email deliverability.
Each blacklist has its own removal (delisting) process. Most require you to visit their website and submit a removal request after fixing the underlying spam issue. Spamhaus delists automatically after 24-48 hours if spam activity stops. Barracuda has a self-service removal portal at barracudacentral.org. SpamCop listings expire automatically within 24-48 hours. Always fix the root cause (compromised server, open relay, malware) before requesting removal.
Common reasons include: a compromised server sending spam without your knowledge, a shared IP on a cloud provider that was previously abused, an open mail relay being exploited, a misconfigured email server, or your IP is in a range that was bulk-listed. Check your mail logs for unusual activity, close any open relays, scan for malware, and update your email authentication (SPF, DKIM, DMARC).
Most DNSBL listings propagate within minutes since they use DNS with very low TTLs (often 300-600 seconds). Delistings also propagate quickly — typically within 30-60 minutes after the blacklist operator removes your entry. However, receiving mail servers may cache the blacklist response for the TTL period, so full recovery can take 1-12 hours.
About This Tool
How It Works
This tool resolves your domain to an IP address, then performs real-time DNS queries against 15 major DNSBL servers. If your reversed IP resolves on a blacklist's DNS, you are listed. All checks run server-side for accuracy.
Blacklists Checked
Spamhaus ZEN, SpamCop, Barracuda, SORBS, UCEPROTECT L1/L2/L3, PSBL, Manitu, Lashback, SpamRATS, ANONMAILS, S5H, DroneBL, Mailspike
The Email Authentication Stack
Staying off blacklists is one part of email deliverability. The authentication stack below prevents spoofing and builds sender reputation — use all of them together for the best results.
| Protocol | What it authenticates | DNS Record | Our Tool |
|---|---|---|---|
| SPF | The sending server's IP address is authorized to send for the domain | TXT at root domain |
SPF Lookup & Generator |
| DKIM | The message was cryptographically signed by an authorized sender and not altered | TXT at {selector}._domainkey.{domain} |
DKIM Checker |
| DMARC | SPF/DKIM alignment with the visible From: header — sets enforcement policy and reporting |
TXT at _dmarc.{domain} |
DMARC Lookup & Generator |
| BIMI | Displays the domain's brand logo in supporting email clients once SPF, DKIM, and DMARC all pass | TXT at default._bimi.{domain} |
BIMI Lookup & Generator |
| Blacklists | Whether the sending IP or domain appears on known spam and abuse blacklists | DNS-based lookup (DNSBL / RBL) | This tool |
