Status of DEAD

An entity called McFadden Associates had been publishing two different, spamtrap-driven DNSBL zones starting from October 2003. Almost ten years later, it appears that these blacklist zones are no more.

The McFadden CSMA blacklist encompassed two different DNSBL zones. The primary zone,, contained only "aggressive" hosts that have spammed repeatedly during a short (recent) timeframe. An additional zone,, had a broader listing criteria, noted by the publisher as more suitable for scoring in a filtering system than outright blocking.

As of January 2013, querying either zone will result in a false positive response, showing that an IP address is blocked, due to a wildcard DNS entry. This means that you should immediately stop using either DNSBL in your spam blocking configuration, otherwise you will reject all inbound mail, legitimate or not.

It's fairly common for a blacklist, when dying, to intentionally or un-intentionally "list the world," answering any DNS lookup request with what amounts to a "yep, that's blocked" response. This regularly causes problems for unsuspecting email system administrators who may still be querying blacklists that are now out of commission. That's why it's important to periodically review your inbound mail server's configuration to revisit what blacklists you might be using and whether or not it makes sense to continue to use them.

In this case, these blacklists are no more, and should be removed from any mail server configurations where they may still linger.

I've reached out to the one-time publisher of these blacklists, and I will follow up with more information if he's able to provide more details.