How to Check If a Domain Is Blacklisted (Step-by-Step)

Blacklist listings happen fast and often without warning. A compromised account, a spam trap hit, or someone spoofing your domain can trigger a listing in hours. Here’s a systematic way to check and act.

What Types of Blacklists Exist

Before checking, understand what you’re actually checking against:

A single domain check should cover all four types simultaneously — otherwise you miss listings that matter.

Step 1: Run a Full Blacklist Check

Go to DomainScan’s Domain Trust Score and enter your domain. The tool automatically:

1. Resolves your MX records to find your outbound mail server IPs
2. Checks those IPs against 130+ IP-based blocklists
3. Checks your domain against domain reputation lists
4. Checks for phishing / malware flags via Google Safe Browsing and PhishTank
5. Returns a composite Trust Score with per-listing details

You don’t need to enter your IP separately — DomainScan extracts it from your DNS.

Step 2: Read the Results

Trust Score and Grade

The Trust Score (0–100) reflects overall domain health — blacklisting is one component alongside DNS configuration, SSL, and email authentication.

• 80–100 (A/B): Clean — no significant listings
• 60–79 (C): Minor issues or warnings — investigate
• 40–59 (D): Active listings on medium-impact lists — act soon
• 0–39 (F): Active listings on critical lists — immediate action needed

Per-Listing Breakdown

Each listing shows:

• List name (e.g., zen.spamhaus.org)
• Listing reason (spam source, malware, phishing, policy)
• Impact level (Critical / High / Medium / Low)
• Direct delist link to the list operator’s removal form

Step 3: Diagnose the Root Cause

Submit delist requests only after fixing the underlying problem. Delisting without a fix means relisting within days.

Common Causes by Listing Type

Spam source listing (IP reputation):

• Compromised email account sending spam
• Misconfigured mail server open relay
• Malware on server sending outbound spam

Check outbound mail volume in your mail server logs or hosting control panel. A spike in sent email you didn’t initiate confirms compromise.

Domain reputation listing:

• Your domain appeared in spam/phishing emails (you may be the victim of spoofing)
• You sent to purchased or stale email lists with spam trap addresses
• A newsletter or bulk email campaign triggered filtering

Run DomainScan’s SPF/DMARC checker — if DMARC is missing or set to p=none, your domain can be freely spoofed.

Malware/phishing listing:

• Files on your web server were modified by attackers
• A compromised plugin or CMS upload created a phishing page

Check recently modified files:

find /var/www -name "*.php" -newer /tmp/baseline -ls 2>/dev/null

Policy block (PBL):

• You’re sending email from a residential or dynamically assigned IP
• Your hosting provider’s IP range is on Spamhaus PBL

Use your provider’s SMTP relay or a transactional email service (Postmark, SendGrid, SES) instead of sending directly.

Step 4: Fix, Then Request Removal

Fixing Compromised Email

1. Reset all email account passwords
2. Enable MFA on your email provider
3. Check mail logs for accounts sending to unfamiliar addresses
4. Revoke suspicious OAuth app access

Fixing Compromised Web Server

1. Scan with a malware scanner (Wordfence, Sucuri, ImunifyAV)
2. Remove or restore compromised files from clean backup
3. Update CMS, themes, plugins to latest versions
4. Patch the attack vector before requesting removal

Submitting Delist Requests

DomainScan links to the removal form for each listing. Common portals:

• Spamhaus: check.spamhaus.org → select your listing → delist
• Barracuda: barracudacentral.org/rbl/removal-request
• Microsoft: sendersupport.olc.protection.outlook.com/pm/delist.aspx
• Google Safe Browsing: safebrowsing.google.com/safebrowsing/report_error/

Most requests are reviewed within 24–48 hours. Spamhaus manual reviews can take 3–7 days.

Step 5: Prevent Future Listings

Checking periodically isn’t enough — use continuous blacklist monitoring so you’re alerted within minutes of a new listing, not days later when deliverability has already tanked.