Product Details

What is the Data Query Service?

The Spamhaus Data Query Service (DQS) is composed of continuously updated IP, Domain & Hash domain name system blocklists (DNSBLs).

Spamhaus blocklists protect against the vast bulk of spam and other email-borne threats at the SMTP gateway.

The outcome is a significant reduction in the time and cost of processing unsolicited and malicious email traffic.

What are DQS System requirements?

These real time DNSBLs can be used with open-source tools like SpamAssassin and Rspamd, or integrated with your existing anti-spam platforms. This keeps costs to a minimum, with no additional hardware required.

Full set up details for DQS are on our documentation page.

Who can use the DQS?

Email administrators and email engineers running their own mail transfer agent or email infrastructure.

You may qualify for a non-commercial account, which is free of charge. See if you meet the usage criteria for a free account.

How to use DNSBLs

Incoming email sent from a blacklisted IP address can be dropped at SMTP connect, saving storage and processing costs. You have the choice to block, accept, or quarantine messages according to your company policy.

When an email is blocked, the sender will immediately receive a notification, ensuring that emails do not lie unread in junk folders for weeks.

Following IP filtering, emails can be filtered by content utilizing our Domain Blocklist (DBL), Zero Reputation Domain Blocklist (ZRD) and Hash Blocklist (HBL). This staged email filtering process is considered best practice:

  1. Remove obvious spam sent from known botnets and spammers’ IP addresses.
  2. Detailed analysis to identify emails containing malware or links to new websites that are controlled by spammers and cybercriminals.

Read “Where to apply blocklists for effective email filtering” for further details.


User and query volume based, with prices starting as low as $250 USD per annum.