Blacklisting is the listing of your IP or domain on a public block list (RBL, DNSBL, Spamhaus, Barracuda…) that flags senders deemed abusive.
Direct consequence: most mail servers query these lists. A blacklisted IP can see 50-90% of its emails blocked or routed to spam.
Why you get blacklisted
- Sudden volume spike from a cold IP
- Too many spam complaints (> 0.1%)
- List containing spam traps
- Missing or broken SPF/DKIM/DMARC
- Purchased or rented lists
- Content flagged as abusive (phishing, fraud)
How to check your status
| Tool | What it checks |
|---|---|
| MXToolbox | 100+ public blacklists |
| Spamhaus | Most consulted by ISPs |
| Mail-Tester | Overall deliverability score |
5 immediate actions to get off the list
- Identify which list flagged you
- Follow that list's delisting process
- Configure SPF, DKIM, DMARC properly (SPF, DKIM, DMARC)
- Clean the list: remove bounces and inactives
- Resume sending gradually (warm-up)
How Mailpro protects you
- Built-in SPF / DKIM / DMARC authentication
- Shared IPs monitored continuously
- Automatic throttling per ISP
- Spam-trap detection before sending
More on the email blacklist definition page, the blacklist blog post, and the deliverability hub.
Protect your sender reputation. Start free with Mailpro and benefit from anti-blacklist monitoring.