The site, the Open Relay Blocking System (ORBS), which provides an automated way of blacklisting third-party email servers that spammers use to send mail, was shut down yesterday. Many email servers by default are open to third-party relay, which spammers use to hide their tracks. Using the ORBS list, ISPs and other email providers can choose to block messages from the offending servers.
ORBS was shut down by its Web host, Canadian telco BC Tel, after BC Tel requested that ORBS warn administrators before testing mail servers for third-party spam relay capability.
BC Tel had received complaints from small ISPs about ORBS's tests, and three months ago requested that ORBS begin warning administrators before testing their mail servers, according to the telco.
ORBS founder and administrator Alan Hodgson declined to comply with that request.
"Everyone tests open relays when they get spam in order to send complaints to right people," Hodgson contended. "If an administrator finds that someone is trying to Telnet into the system, it may be a sign that someone is trying to break in. But BC Tel knows the nature of this service."
While ORBS is homeless for the time being, it probably will not be for long. A notification of the site's demise, posted by Hodgson to several newsgroups yesterday, already has elicited ten offers to host the service.
Since its June launch, ORBS has seen 15,000 systems secure their servers against spammers after the servers were added to the blacklist. Hodgson estimates that between 70 and 80 sites, with an estimated total of several hundred thousand email users, use the list.
ORBS, formerly located at www.dorkslayers.com, is not alone in blacklisting spam relay servers. Another such service is the Mail Abuse Protection System's Realtime Blackhole List, or MAPS RBL, which has succeeded in pressuring some high-profile sites to block spammer from using their servers.