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Status of spamtrap.trblspam.com: DEAD

The DNSBL spamtrap.trblspam.com appears to have gone offline as of April 2, 2013. It appears to have been created in early 2011 by somebody known as "Tom from TRBL," whom I observed participating in various email discussion lists. I've emailed Tom and will update this page if I receive any further details.

I recommend removing spamtrap.trblspam.com from any blocklist checking you're doing. Any time a list is shut down, there's a chance that they will end up putting in a wildcard DNS record, which ends up effectively "listing the world" and causing problems for any receiving sites who still have that DNSBL configured in their mail server configuration.

(Thanks to Martijn Grooten for the heads up.)

Status of dnsbl.njabl.org: DEAD

It is with sadness that I report  on the closure of Jon Lewis's NJABL blocking list.  From the NJABL website: "March 1, 2013: NJABL is in the process of being shut down. The DNSBL zones have been emptied. After "the Internet" has had some time to remove NJABL from server configs, the NS's will be pointed off into unallocated space (192.0.2.0/24 TEST-NET-1) to hopefully make the shutdown obvious to those who were slower to notice."

NJABL (Not Just Another Bogus List) had been in existence from at least January 2002. Congrats to Jon and team for a pretty good run of eleven years.

Update: I received this in email: "Today, April 29, 2013, NS for the NJABL DNSBL zones is being pointed into 192.0.2.0/24 (TEST-NET-1) which is unrouted IP space.  This will likely cause any systems using the NJABL DNSBL zones to experience long delays in DNS resolution of NJABL DNSBL lookups.  This is being done both to sink the DNS query traffic and to hopefully be noticed by the owners/managers of those systems."

(H/T: Laura Atkins and others.)

Status of bl.csma.biz: 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 blocklist zones are no more.

The McFadden CSMA blocking list encompassed two different DNSBL zones. The primary zone, bl.csma.biz, contained only "aggressive" hosts that have spammed repeatedly during a short (recent) timeframe. An additional zone, sbl.csma.biz, 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 list, 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 blocking lists that are now out of commission. That's why it's important to periodically review your inbound mail server's configuration to revisit what DNSBL lists you might be using and whether or not it makes sense to continue to use them.

In this case, these lists 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 lists, and I will follow up with more information if he's able to provide more details.




Status of rfc-ignorant.org: SHUTTING DOWN

One-time Yahoo administrator Derek Balling has announced that the RFC Ignorant blocking list is being shut down. This blocking list had existed since at least late 2001. Its listing criteria including things like not having an "abuse" or "postmaster"address that accepted mail. Listing criteria didn't necessarily overlap with the generally accepted criteria for fighting spam, so my guess is that this blocking list's lack of usefulness as a spam fighting tool had finally diminished past the point of no useful return. As Derek himself says, "the usefulness of a DNSBL is greatly diminished," and of the old hardware running the service, "the value proposition just isn't there."

I blogged about the RFC Ignorant blocking list back in 2006.

Status of blackholes.five-ten-sg.com: DEAD

The "Fiveten" Blocklist (blackholes.five-ten-sg.com) was a combination anti-spam blocking list run by Carl Byington, publishing under the name of "510 Software Group." This blocking list has been available since at least February, 2001, and it appears to have been retired as of April 2012.

As of late April, 2012, any attempt to look up an entry on the list results in output indicating that "The blackholes.five-ten-sg.com list is retired. No ip address is listed here." Meaning, the list is no longer in operation.

I had previously written about this list back in October, 2007, and my 2007-2008 DNSBL statistics project data showed that the list may not be suitable for broad production use if one wishes to receive requested email messages. The list has been up and down at various other times, most recently being taken offline for a period in November 2010.

(Hat tip: Word to the Wise)