ORDB anti-spam blacklist lists everything
For more than a year the ORDB blacklist, which had previously been in heavy use, has been empty. Every DNS query to the relays.ordb.org zone would result in the error message, "non-existent".
To report a hit, DNS queryable blacklists (DNSBLs) usually respond with an IP address in the 127.x.x.x range and since Tuesday, the name server responsible for the name range under relays.ordb.org does just that for every query, such as 184.108.40.206.any.relays.ordb.org. Andreas Plesner Jacobsen, a former ORDB operator, explained to heise online sister publication iX that this measure has been introduced because the zone is still swamped with queries. The intention is to get mail server operators to stop using ORDB. Simply deleting the domain was not a viable alternative, since the load would then merely be directed to the .org name server.
Admins should check their mail server and spam filter configurations to make sure that ORDB is not in use. This should be relatively easy to determine in most cases, since positive responses from DNSBLs often result in emails being filtered and in this case would completely stop email traffic. A somewhat more complicated scenario is when DNSBL responses are taken into account as just one of a number of spam criteria. In that case, yesterday's new measure would only gradually become known to postmasters still using ORDB.