The Spamhaus Project


If you query the legacy DNSBLs via OVHCloud move to Spamhaus Technology's free Data Query Service

Are you currently using the Spamhauss DNS Blocklists (DNSBLs) via OVHCloud? If you've answered "yes" to both of these questions, you need to make some changes to your email infrastructure.

by The Spamhaus TeamMay 17, 20234 minutes reading time

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If you are currently accessing the legacy DNS Blocklists (DNSBLs) via the Public Mirrors, and you’re using OVHCloud infrastructure – you’ll need to make some minor changes to your email infrastructure. The changes are easy to implement, but if you fail to do so, you could find that at some point post-June 20th 2023, all or none of your email is blocked!### The headlines for those in a hurry

Our Terms of Use state that we do not allow users to query via DNS resolvers where there is no attributable reverse DNS; this includes OVHCloud (we’ll explain why later in this article).

To provide a clear signal to these users that these blocklists are not protecting their email, we will return an error code; If you haven’t set up your email servers to accept this error code, all emails could be rejected and bounced back to their sender.

To prevent any issues with your email stream, stop accessing the free blocklists via the Public Mirrors and start accessing the blocklists via Spamhaus Technology's free Data Query Service (DQS), which you can sign up for here.

Once you’ve verified your email address, you will get access to a “DQS key” to include in your configuration. These config changes take only minutes; see our technical docs for more detail.

Why isn't Spamhaus allowing OVHCloud users to query the public blocklists?

The blocklists that we make freely available via the Public Mirrors are for small-scale, non-commercial use. To ensure these users have a good quality of service, usage is monitored and measured against the Project’s Terms of Use.

OVHCloud masks organizations’ queries to the Public Mirrors, so the team can’t attribute usage to individual entities. They have no way of establishing the number of queries a single organization is making.

To provide transparency, these free blocklists can be accessed via the free Spamhaus Technology DQS.

How is Spamhaus Technology's free DQS different from the free Public Mirrors?

How to access Spamhaus Technology's free DQS

  1. Sign up for an account
  2. Verify your email address
  3. Log in to your account and access your DQS key
  4. Update your email configuration. We have config guides for mainstream MTAs.

How will OVHCloud users be prevented from querying the free DNSBLs?

To ensure the Terms of Use are adhered to, we will block queries from a specific IP address outside the policy. We will also return an error code. In the case of querying via an open/public resolver, i.e., OVHCloud, the error code is

If your MTA can’t correctly parse these error codes, serious issues can occur, including bouncing all emails back to their senders and your emails not being queried against the blocklists. Here’s how to properly configure your MTA to process these error codes, if you continue to use the free DNSBLs.

When will the error code for OVHCloud DNSBL users be introduced?

We will slowly implement the error code across OVHCloud’s IP space, commencing from Tuesday, June 20th, 2023.

Please don’t delay – take action now and move to the free DQS.

What if I don’t want to use Spamhaus Technology's free DQS?

  1. Use DNS resolvers with attributable DNS to continue being protected by Spamhaus’s IP and domain reputation.
  2. If you no longer wish for your mail stream to be protected for free by Spamhaus’ blocklists, remove all associated configurations from your email infrastructure.

Further details

Additional information for free DNSBLs users having issues due to error codes is detailed here.

Previous communications that sent in relation to these changes can be found here:

Any questions?

Not a problem – reach out to us via Twitter @spamhaus and we'll get back to you with a response.

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