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Have you been blocked?

All blocklists are researched and managed by The Spamhaus Project.

Simply click on the link below, which will take you to the Project’s IP and Domain Reputation Checker. From here you will be able to enter your IP or Domain and begin your request for removal.

Please note that the Project’s IP and Domain Reputation Checker is the only place where removals are handled.

Visit Spamhaus Project

If your email infrastructure relies on Microsoft’s network and you’re using The Spamhaus Project’s free legacy DNS Blocklists (DNSBLs) through the Public Mirrors, it’s time to make an important update. To ensure continued protection and prevent potential email disruptions, you should transition to the free Data Query Service (DQS) before April 9th, 2025.

Key takeaways

  • The Spamhaus Project’s fair use policy prohibits DNS queries from resolvers or servers without attributable reverse DNS – this includes Microsoft’s infrastructure.
  • To signal that the free Public Mirrors are no longer providing protection, queries from Microsoft will return the error code 127.255.255.254.
  • If your mail server does not handle this error code correctly, it may reject all emails.
  • To maintain seamless email filtering, migrate to the free Data Query Service. Sign up here.
  • Configuration changes are simple and quick – see our technical documentation for details.

Why are Microsoft users affected?

The free Public Mirrors are designed for small-scale, non-commercial use. The Spamhaus Project monitors usage according to its fair use policy to ensure fair access and a high-quality service. 

However, Microsoft’s default reverse DNS setup prevents The Spamhaus Project from attributing queries to individual organizations. This makes it impossible to determine whether usage falls within acceptable limits, necessitating a block on queries originating from Microsoft.

Why move to the FREE Data Query Service?

DQS offers several advantages over the free Public Mirrors:

Steps to access the free DQS

When will Microsoft queries be blocked?

The block will be introduced gradually, from Wednesday, April 9th, 2025.

What if I don’t want to use the free DQS?

Alternatively,  you can use a DNS resolver with an attributable reverse DNS to continue to be protected for free by The Spamhaus Project’s DNSBLs.

If you choose not to continue using The Spamhaus Project’s DNSBLs, you’ll need to remove all related configurations from your email infrastructure

Need more information?

Learn more about Spamhaus Project’s DNSBL return codes.

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