A blacklisted domain is one that has been flagged by security services, email providers, or search engines as untrustworthy. The consequences are severe: emails sent from the domain bounce or land in spam, browsers display security warnings to visitors, search engines suppress or remove the site from results entirely, and advertising platforms refuse to serve ads. If you’ve recently purchased a domain, noticed a sudden drop in email deliverability, or inherited a website with an unknown history, checking for blacklist status should be your first diagnostic step.
How to Check Your Domain’s Reputation
Start with our Domain Reputation Checker, which runs four automated checks that cover the most common indicators of domain health problems: HTTPS status, DNS configuration, email authentication (SPF and DMARC), and domain age assessment. If any of these checks fail, you’ve identified a specific issue to investigate.
For deeper blacklist checking beyond our automated scan, these free external tools check specific databases:
Google Safe Browsing maintains a database of sites known to distribute malware or host phishing pages. If your domain is flagged here, Chrome, Firefox, and Safari will display a full-page warning before allowing visitors to proceed. You can check your status at Google’s Transparency Report (transparencyreport.google.com/safe-browsing/search). Getting delisted requires fixing the security issue and submitting a review request through Google Search Console.
Spamhaus operates some of the most widely used email blacklists. If your domain or your server’s IP appears on Spamhaus’s DBL (Domain Block List) or SBL (Spamhaus Block List), most major email providers will reject your emails outright. Check your status at check.spamhaus.org. Delisting involves identifying and fixing the spam source, then requesting removal.
MXToolbox aggregates over 100 blacklist databases into a single lookup. Their blacklist check at mxtoolbox.com/blacklists.aspx is the most comprehensive single-query option for email-related blacklists.
VirusTotal scans domains against 70+ security vendors’ databases simultaneously. If your domain is flagged by multiple security vendors on VirusTotal, the problem is serious and likely involves active malware or phishing content on the site.
What Causes Blacklisting
The most common cause for domains that were recently purchased is inherited history. The previous owner may have used the domain for spam email campaigns, hosted malware, run phishing operations, or built a link farm. Even if the content has been completely replaced, blacklist entries from the previous usage persist until you actively request removal. This is why running a domain age check and reputation scan before buying is essential due diligence.
Compromised websites are the second most common cause. If your WordPress site was hacked and injected with malware or spam links, security services may have flagged your domain before you even noticed the breach. Outdated plugins, weak admin passwords, and unpatched themes are the typical entry points.
Missing email authentication doesn’t directly cause blacklisting, but it makes your domain vulnerable to being spoofed. If spammers send emails that appear to come from your domain and you have no SPF or DMARC records to prove those emails weren’t authorized by you, your domain’s reputation degrades as recipients report the spoofed emails as spam. Use our DNS lookup tool to verify your SPF and DMARC TXT records are in place.
How to Fix a Blacklisted Domain
First, identify and fix the root cause. If the site was compromised, clean the malware, update all software, and change all passwords. If the domain was previously used for spam, ensure the current site content is legitimate and the DNS records are properly configured.
Second, add email authentication records if they’re missing. Set up SPF to authorize your legitimate email servers. Configure DKIM through your email provider. Add a DMARC record with at minimum p=quarantine to tell receiving servers what to do with unauthorized emails.
Third, install a valid SSL certificate if one isn’t already active. A domain serving content over HTTP without encryption is an immediate red flag for security services.
Fourth, submit removal requests to each blacklist service that has flagged your domain. Each has its own process — Google requires a review through Search Console, Spamhaus has a self-service removal form, and most DNSBL services provide automated delisting after a waiting period once the issue is resolved.
Finally, monitor your domain’s reputation on an ongoing basis. Run a reputation check monthly to catch new issues before they escalate. Blacklisting can recur if the underlying vulnerability isn’t fully addressed.
