Beginning on July 1, Spamhaus will be publishing new return codes for its DBL list. My colleague, Christine Borgia, has already blogged about its effect on senders, but I wanted to take a moment to discuss how consumers of the DBL might be impacted.
The goal of the changes, which are shown in the table below, is to introduce more granularity to the response codes, and better identify the reason for a domain being listed. Up until now, there have only been three codes, but the coming changes will introduce seven new ones, and replace one of the existing ones (127.0.1.3) with a new one (127.0.1.103).
What Does This Mean For You?
Well, the answer to that question is “It depends”. If your usage to date of the DBL has been essentially binary (meaning you take one action for any positive DNSBL query response, and you do nothing for any negative query response) then this change will be a non-event for you. On the other hand, if you’ve chosen to tie your action taken to the response code (e.g., block for 127.0.1.2, but filter for 127.0.1.3), you’ll have some work to do to update your usage of the DBL. At a minimum, you’ll want to change the check for a response of 127.0.1.3 to a check for 127.0.1.103, since the former will be phased out in January, 2015. Beyond that, the new codes give you the opportunity, if you wish, to add a new or discrete action to your mail system for each response code.
More information on this change can be found at Spamhaus' website.