In.dnsbl.org

From Wiki.openrbl.org

As posted to NANOG:

in.dnsbl.org was created several years ago for commercial DNS providers to share information about problem domains and to offer a mechanism to prevent abusers from hopping from DNS provider to provider.

Under no circumstances should it be used by any MTA for mail filtering in any capacity whatsoever. Absolutely no vetting goes into in.dnsbl.org listing and domains can get listed for internal reasons which are purely meaningless in an email context.

Over the years some big name domains have wound up in the in.dnsbl.org zone for reasons which have absolutely nothing to do with email and simply for inter-provider communications between the DNSBL.org members.

In short, using in.dnsbl.org on any MTA is an act of mind-numbing recklessness. Don't do it.

Thank you for your time.

Addendum from their site the ex.dnsbl.org zone The ex.dnsbl.org zone is an ancillary zone to the dnsbl.org system. It can be used as a domain based DNS-bl. When spammers are kicked off a partcipating DNS provider's system, they are put into the *.ex.dnsbl.org zone.

The ex.dnsbl.org zone can be used by DNS providers or other interested parties to screen prospective clients before they move onto the system in the first place or even filter email at the hub level. The zone breaks down as follows:

127.0.0.2 domain has been banned for spamming easyDNS corporate mail hubs. 127.0.0.3 domain has been banned from easyDNS mailhubs. The domain has been added for the sole reason that has been spamming easyDNS customers. Addition to the ex.dnsbl.org zone with this value is done purely at the discretion of easyDNS and is not open to appeal. Domains that wind up here deserve it and it is pretty safe to filter these values at your mail hubs (you will probably eliminate a lot of spam by doing so).