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Background, whose parent company is LashBack uses what is called an unsubscribe intelligence database for the creation and maintenance of it's DNS blacklist. LashBack has been in operation since 2003. Spammers deploy what are known as suppression lists, also known as unsubscribe forms. When a spam is sent with a link to unsubscribe you address from the mailing, your address should in theory be removed. Often times, the opposite happens, and your address is then considered more valuable, and resold to other spammers as a known deliverable address. has systems in place that will use trackable email addresses to unsubscribe from the suppressions lists. Over time, they can track which suppressions lists are good, and which are actually sharing their suppression lists with other spammers. When this type of activity is apparent, the IP address of the sender is added to the DNS blacklist.

Listing criteria

LashBack uses 4 criteria when monitoring unsubscribe compliance.

  1. Which senders fail to provide a working unsubscribe mechanism
  2. Which senders do not honor unsubscribe requests within 10 business days
  3. Which senders allow consumers unsubscribe request to be abused (i.e., shared with other parties to send more spam)
  4. Which senders are taking suppression lists from other organizations and sending email to these lists

Criteria 1, 2, and 3 are used for internal purposes, as well as research. The data from criteria 1 through 3 can usually be obtains by making a request to LashBack's support system. Only criteria 4 is used for the moderation of the actual DNS blacklist.


Like all other DNS blacklists, to use the LashBack DNSBL, a query is made against The criteria are to send in the reverse IP of the sending server, appending on the zone. In the case of, you will be looking for a specific response on, which means, that sender has been seen abusing unsubscribe data.

Removal Process

At this time, does not give any data on the process by which you can have your IP address removed. There is however, a IP based removal form, that if your IP is listed, should have instructions on who to contact in an effort to have your IP removed. Given that only lists the most egregious of offenders, removal may not be a top priority.

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