How to check if your IP is on a blocklist – and what to do if it is
Many mailbox providers check the IP address your mail comes from against blocklists. If it is listed, your mail lands in spam or is rejected, even when SPF, DKIM and DMARC are correct. Here is how to check, and what to do if you are listed.
Check your IP and domain
Enter the sending IP or your domain in the blocklist check. It queries the main lists in one step.
You can also check the big lists yourself: Spamhaus (ZEN for IP addresses, DBL for domains), Barracuda and SpamCop. Each list has its own rules and its own removal process. A listing on one list does not mean the others list you too.
If you are listed
- Find the cause. Common causes are a hacked mailbox, a contact form that sends spam, an open relay, or old mailing lists that were never cleaned.
- Fix the cause. Removal without a fix usually leads to a new listing.
- Request removal. Spamhaus removes listings free of charge via check.spamhaus.org, and it says that paid removal offers are a scam. Some listings end on their own once the criteria are no longer met. There is no fixed period to rely on.
For a step-by-step guide to a specific list, see how to remove an IP or domain from a blacklist.
Shared servers and provider IPs
If you send from a shared server or your provider's network, you share the IP with other customers. A listing then affects you without any fault of your own. In that case contact your provider, or send from a dedicated server or an authenticated sending service.
Your domain can be listed too
Your domain can appear on domain blocklists, for example when it is used in links or in spam. Check the domain as well as the IP, for instance with the domain blacklist check.