Thread by @spamhaus

If you're using our public mirrors, you need to check your return codes, and soon... here's why. spamhaus.org/news/article/8…

#returncodes #config #MTA #Spamhaus

We are implementing 3 new return codes in March. These are error codes, not reputation codes.

If you are not parsing these codes correctly all query responses may be treated either as "LISTED" or "NOT LISTED." Both results may potentially have disastrous outcomes.

Confirm that any software querying the public mirrors can distinguish between the error codes and the valid reputational codes we provide for our lists.

Error codes mean that the query is blocked, and it will return no reputation data.

So, as of March make sure you check your logs and take the necessary action where error codes are found.