By Neil Schwartzman
Senior Director, Security Strategy, Receiver Services
Recently, I wrote about the Spamhaus Policy Block List (PBL), suggesting senders encourage their network/connectivity service providers (whomever they lease or purchase IP addresses from) to list their illegitimate email-sending IPs as a step towards improving the overall email stream on the internet.
The initial PBL was seeded with listings from the Dynablock NJABL (“Not Just Another Bogus List”), which at the time of the cut-over was at more than 1.9 million entries. (Dynablock is now considered to be moribund and will be taken down in due course.)
The organic uptake at Spamhaus has been phenomenal: as of yesterday, the PBL has listings for almost 226 million IPs to be blocked. That’s an increase in size of 16% in less than one month. The PBL has averaged about 1.7 million additions per day over the past two weeks.
Again, encourage your connectivity service provider to list their dynamic IP ranges with the PBL, to help further the gap between legitimate email sources, and those IPs of zombie machines forming botnets.