Quick note about ORBS: there are people ORBS blocks (such as GOL in Japan) which do not have any open relays, and never did. It's purely a personal grudge held by the ORBS operator.
Having bought into the "only open relays" and "only automated testing" claims of ORBS, I was doubtful here. I was a bit shocked to find all of 203.216.0.0/16 in the zonefile for ORBS and asked the ORBS maintainer about it. He replied: The administrator 203.216.0.0/16 specifically requested ... actually ... demanded that his address space be added to ORBS and that I forever desist from testing his addresses or notifying him of open relays. I had about 70 open relays listed in that range at that time. Since he requested that the entire space be added to ORBS, I complied. This is the only address space in ORBS that comprises more than one address and which each address has not specifically been tested to be open relays. He attached copies of mail from abuse@gol.ad.jp which more or less request exactly that. Copies are available upon request. I also looked through the zonefile a bit more and found no other wildcards. Apologies to those of you trying to drop the spam thread. Aaron Hopkins Chief Technology Officer Cyberverse, Inc.