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.
The most common reasons are: sending spam (either intentionally or via a compromised account), malware hosting, operating an open relay, and being part of a botnet. Cloud providers like AWS, DigitalOcean, and Azure have entire IP ranges listed on some blacklists because they are frequently abused. Even a brief period of abuse can result in a listing that persists long after the activity stops.
Each blacklist operates its own delisting process — there is no universal removal form. Spamhaus provides lookup and removal links per listing at sbl.spamhaus.org. Barracuda Central offers a self-service portal at barracudacentral.org/rbl/removal-request. SORBS requires submitting a delisting request on their website. Before submitting any request, fix the root cause — otherwise you will be relisted shortly after removal.
The most widely used by mail servers include: Spamhaus SBL (known spam sources), Spamhaus XBL (compromised IPs and botnets), Spamhaus PBL (end-user IP ranges that should not send email directly), Barracuda BRBL, and SORBS. Being listed on Spamhaus in particular will cause severe deliverability problems because it is queried by a very large proportion of mail servers worldwide.
Listing duration varies widely. SpamCop listings expire automatically within 24–48 hours after the last spam report. Barracuda listings can persist indefinitely until a manual removal request is submitted. Spamhaus SBL listings remain until Spamhaus manually removes them after verifying the abuse has stopped. The faster you stop the abuse and fix the root cause, the shorter the listing period will typically be.
Yes. On shared hosting plans, many websites share the same IP address. If one of your neighbours on the same server sends spam or hosts malware, the shared IP can be blacklisted — affecting all sites on that server. To mitigate it, use a dedicated IP for your mail server or upgrade to a VPS. Transactional email services like SendGrid, Mailgun, or Amazon SES operate large pools of pre-warmed IPs and handle blacklist monitoring automatically.
IP blacklists (DNSBLs) list specific IP addresses known to send spam and are checked against the sending mail server's IP. Domain blacklists — such as SURBL and URIBL — list domain names that appear in spam message bodies (the URLs spammers include in their emails). A domain can be on SURBL/URIBL even if its hosting IP is clean, because spammers often use legitimate hosting to serve their landing pages.

About This Tool

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.

ProtocolWhat it authenticatesDNS RecordOur Tool
SPFThe sending server's IP is authorizedTXT at root domainSPF Lookup & Generator
DKIMMessage signed and not alteredTXT at {selector}._domainkeyDKIM Checker
DMARCSPF/DKIM alignment; enforcement policyTXT at _dmarc.{domain}DMARC Lookup & Generator
BIMIBrand logo in email clientsTXT at default._bimi.{domain}BIMI Lookup & Generator
BlacklistsWhether sending IP/domain is on spam listsDNS-based lookup (DNSBL / RBL)This tool

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