Differences between DQS and Spamhaus “free service”

While from the access technology perspective DQS is not particularly different from the DNSBL service provided by Spamhaus, there are a few important differences between the two you may want to be aware of.

While most of the data are the same, there are a few differences.

  • some SBL listings that are considered more prone to False Positives are not published on DQS
  • DQS data are updated in realtime when new listings appear, unlike the public mirrors, that get only updated at scheduled intervals
  • some datasets are only available on DQS and will never be provided by public mirrors
  • access to public mirrors requires the use of a non-public, non-shared DNS resolver (therefore excluding services like Google Public DNS), while DQS can use any DNS channel
  • access to public mirrors can be inhibited anytime for a number of reasons, usually related with overquerying or observed malicious behavior from the querying network