How to Check If Your Domain Is on an Email Blacklist (and Get Removed)

If your emails are bouncing, landing in spam, or getting blocked outright, your sending domain or IP may be on a DNS-based blacklist (DNSBL). Here's how to check every list that matters, why you ended up there, and how to get removed — with steps for the five most common blacklists.

What is an email blacklist?

Email blacklists (also called DNSBLs or RBLs — Realtime Blackhole Lists) are databases of IP addresses and domains known or suspected to send spam, malware, or phishing email. Mail servers check these lists in real time and use the results to decide whether to deliver, reject, or mark your email as spam.

There are over 100 public blacklists, but only a handful are widely used by major mail providers. Getting on one of the major lists (Spamhaus, SORBS, Barracuda) can silently kill your email deliverability overnight.

The 7 blacklists that actually matter

How to check if you're blacklisted

Quick check (3 tools)

1. MXToolbox Blacklist Check (mxtoolbox.com/blacklists.aspx) — checks your IP against 100+ lists in one query. Free.
2. Spamhaus Lookup (check.spamhaus.org) — check your domain directly against all Spamhaus lists.
3. Google Postmaster Tools (postmaster.google.com) — requires DNS verification of your domain, but gives you Gmail-specific reputation data (domain reputation, IP reputation, spam rate).

Finding your sending IP

You need to check the IP your mail server sends from, not your website IP. Find it by:

• Looking at the "Received" headers of an email you sent: Received: from mail.yourdomain.com ([203.0.113.42])
• In Google Workspace: Admin Console → Apps → Google Workspace → Gmail → Default routing — your outbound IP is shown
• In M365: the sending IPs are Microsoft's shared pools (check via Microsoft's IP documentation, or look in your email headers)

Why domains and IPs get blacklisted

• Spam complaints: Too many recipients marked your email as spam. Even 0.3% complaint rate can trigger a listing.
• Hitting spam traps: Sending to old, invalid, or honeypot addresses that blacklist operators seed into leaked lists.
• No DMARC / SPF misconfiguration: Your domain was spoofed and used to send spam. The spam filters listed your domain even though you didn't send anything.
• Compromised account: A user account was breached and used to send bulk spam from your infrastructure.
• Shared IP reputation: You share a sending IP (common on cheap hosting) with a spammer. Their behavior affected your reputation.
• Sudden volume spike: Sending a large campaign from a domain with low prior volume triggers spam filters.

How to get removed from the major blacklists

Spamhaus (SBL/DBL)

1. Go to check.spamhaus.org and look up your IP or domain
2. Click on the listing to see the reason
3. Fix the underlying issue (compromised account, open relay, domain spoofing)
4. Submit a removal request at spamhaus.org/lookup — you'll need to explain what you fixed
5. Spamhaus typically responds within 24–48 hours for legitimate requests

Barracuda BRBL

1. Check at barracudacentral.org/lookups
2. Click "Request removal" — for IPs with low complaint history, removal is usually automatic
3. For repeat listings, you'll need to submit a full removal request with explanation

Google Postmaster

Google doesn't have a manual removal process. Your domain reputation recovers as you send clean email with proper authentication (SPF, DKIM, DMARC) and low complaint rates. This takes time — typically 2–4 weeks of consistent, clean sending.

Prevention checklist

• DMARC set to p=reject (prevents spoofing that can get your domain listed without your knowledge)
• SPF record covers all legitimate sending sources — no +all or missing sources
• DKIM configured for all sending services (Google, Mailchimp, SendGrid, etc.)
• Maintain a clean email list — remove bounces and unsubscribers promptly
• Use a dedicated sending IP or reputable ESP (avoid shared hosting IP pools)
• Monitor your sending reputation via Google Postmaster Tools and Microsoft SNDS
• Set up weekly blacklist monitoring — Pulse Pro includes blacklist monitoring in its weekly digest