News: Nope, still not listed at Spamhaus
Every day we see a few outbound emails rejected, claiming our sending IP to be listed at Spamhaus. Those users who sent those emails will receive a message back making this same claim, that an IP of ours is listed at Spamhaus. It isn't true, not even a little. Such an event would be nuclear in our field, we wouldn't let it slide for a moment. So let me tell you what is actually happening:
Spamhaus does not accept queries using public DNS servers. Using public DNS servers is actually one of the most common things that people configure servers to do. Recently, they've been cracking down on their policy and actually rejecting the queries. Many of the servers in question interpret this rejected query as a blacklisting, even though it isn't.
Most system administrators who notice this behavior quickly resolve it, but this will impact a lot of people who were not prepared for it. There isn't much we can do about it other than spread the word, so please do.