A blacklist listing can appear without warning after a security incident, compromised account, or spam trap hit. Here’s how to use DomainScan to check your standing and act fast if you’re listed.
What Gets Checked
DomainScan’s blacklist checker queries two things:
- Your domain: checked against domain-based lists (SURBL, URIBL, Spamhaus DBL, Phishtank, Google Safe Browsing)
- Your mail server IP: automatically extracted from your MX records and checked against IP-based lists (Spamhaus ZEN, Barracuda, SORBS, SpamCop, and 40+ others)
Enter just your domain — DomainScan resolves your MX records and checks the IPs automatically.
Reading the Results
Green — Not Listed
Your domain and IPs are clean on all checked lists. If you’re still having deliverability problems, the issue lies elsewhere — check email authentication or content/reputation factors.
Red — Listed
The report shows:
- Which list you’re listed on (e.g.,
zen.spamhaus.org) - Listing type (spam source, phishing, malware hosting, policy block)
- Impact level (High / Medium / Low based on how widely the list is used)
- Delist link direct to the list operator’s removal form
Yellow — Warning
Some lists flag IPs or domains as “suspicious” without full listing. This typically means you’re on a monitoring list or have traits associated with spam (e.g., no reverse DNS, newly registered domain). No immediate action required, but address the underlying factors.
Priority: Which Listings to Fix First
| Listing | Impact | Fix Priority |
|---|---|---|
| Spamhaus ZEN/SBL/XBL | Critical — blocks email at Gmail, M365, Yahoo | Immediate |
| Barracuda BRBL | High — used by enterprise mail gateways | Within 24h |
| Microsoft SmartScreen | High — affects Outlook/Hotmail delivery | Immediate |
| Google Safe Browsing | High — browser warnings, affects site traffic | Immediate |
| SURBL / URIBL | Medium — affects email content filtering | Within 48h |
| SpamCop | Medium — used by some ISPs | Within 48h |
| SORBS | Low-Medium — older list, less widely used | Within 1 week |
| Smaller obscure lists | Low — minimal real-world impact | As time allows |
Steps After Finding a Listing
1. Identify the Root Cause
Don’t submit a delist request before fixing the problem — you’ll be relisted within days.
| Listing Reason | Likely Cause | Fix |
|---|---|---|
| Spam source | Compromised email account or server sending spam | Reset passwords, enable MFA, check mail logs |
| Malware hosting | Malicious files on web server | Scan and clean all files, update CMS/plugins |
| Phishing | Fake login page on your domain | Remove page, audit all hosted files |
| Policy block (PBL) | IP in dynamic/residential range shouldn’t send email | Use your hosting provider’s dedicated SMTP |
| Spam trap hit | Sending to old/purchased email lists | Clean list, switch to confirmed opt-in |
2. Fix the Root Cause
Depending on the type:
Compromised server / spam source:
# Check outbound mail logs for unexpected activity
grep "status=sent" /var/log/mail.log | grep -v "@yourdomain.com" | head -50
# Look for PHP scripts sending mail
grep -r "mail(" /var/www/html --include="*.php" | grep -v vendorMalware on web server:
- Run a malware scanner (Wordfence for WordPress, ImunifyAV for cPanel)
- Review file modification dates:
find /var/www -newer /tmp/baseline -name "*.php" 2>/dev/null - Restore from a clean backup taken before the compromise
3. Submit Delist Requests
DomainScan links directly to each list’s delist form from the results. Common delist portals:
- Spamhaus: lookup.mxtoolbox.com → click the Spamhaus listing → delist link
- Barracuda: barracudacentral.org/rbl/removal-request
- Microsoft: sendersupport.olc.protection.outlook.com/pm/delist.aspx
- SORBS: sorbs.net/lookup.shtml
Most requests are processed within 24-48 hours. Spamhaus’s DBL and SBL can take 3-7 days for manual review.
4. Monitor for Re-Listing
Enable blacklist monitoring in DomainScan to receive email alerts if you’re listed again. Re-listing within days of removal usually means the root cause wasn’t fully addressed.
Preventing Future Blacklisting
- Enable DMARC
p=reject— prevents your domain from being used in phishing campaigns - Use confirmed (double) opt-in for email lists — eliminates spam trap hits from stale addresses
- Monitor Google Postmaster Tools spam rate — keep under 0.1%
- Keep your CMS, plugins, and server software patched
- Enable MFA on all email accounts
- Set up PTR (reverse DNS) for your mail server IP
Common Questions
Which blacklists matter most?
Spamhaus (SBL, XBL, ZEN) is the most critical — it's queried by Gmail, Microsoft, Yahoo, and most enterprise mail gateways. Barracuda BRBL and SORBS are also widely used. Being listed on an obscure list with low adoption has minimal real-world impact. DomainScan highlights high-impact listings separately so you know which to prioritize.
My IP is clean but my domain is blacklisted. Does that affect email?
Domain blacklists (SURBL, URIBL, Spamhaus DBL) primarily affect email where your domain appears in the message body or headers — common in phishing or spam campaigns that reference your domain. The impact depends on which list and how it's used. Domain blacklisting can also affect browser warnings via Google Safe Browsing. Fix the root cause (malware, phishing content) and request delisting.
How often should I check for blacklisting?
Set up continuous monitoring rather than checking manually. Blacklisting can happen within hours of a compromise or spam campaign. DomainScan's monitoring alerts notify you by email within minutes of a new listing, so you can take action before your email deliverability is severely impacted.