Key takeaways
- The Spamhaus Project’s fair use policy prohibits DNS queries from resolvers or servers without attributable reverse DNS - this includes Oracle’s cloud infrastructure.
- To signal that the free Public Mirrors are no longer providing protection, queries from Oracle 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 DQS. Sign up here.
- Configuration changes are simple and quick - see our technical documentation for details.
Why are Oracle 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, Oracle’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 Oracle.
Why move to the FREE DQS?
DQS offers several advantages over the free Public Mirrors:
- Transparent usage – Register for FREE and receive a key that tracks query volume.
- Improved performance – Blocklists are updated in real-time, ensuring the latest threat intelligence.
- Expanded protection – Access additional blocklists, including: Zero Reputation Domain BlocklistDomain Blocklist with HostnamesAuth Blocklist
Steps to access the free DQS
- Remove all legacy Spamhaus Project DNSBL configurations before signing up to ensure you receive your verification email.
- Sign up for a DQS account.
- Verify your email address.
- Log in to your account and retrieve your DQS key.
- Update your email configuration using our guides for mainstream MTAs.
When will Oracle queries be blocked?
The block will be introduced gradually, from Wednesday, April 8th, 2026.
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.
- Read previous announcements from The Spamhaus Project: Using our public mirrors? Check your return codes now.
- For more help: Contact us via Twitter @spamhaustech, LinkedIn @Spamhaus-Technology-ltd, or our contact form.