Spamhaus launches whitelist
Spamhaus, previously known mainly for its anti-spam blacklists, is launching an online whitelist project. Spamhaus said that checking whitelists as well as blacklists allows users to improve their spam filtering. According to Spamhaus, emails originating from whitelisted mail servers can pass unfiltered, while emails from blacklisted servers can be blocked as before. As a consequence, said Spamhaus, fewer emails than before need to be processed via more elaborate secondary filters. Reportedly, this reduces processing loads and errors.
The Spamhaus whitelist is to include "qualified corporations" such as banks, accounting firms and airlines as well as medical centres and government agencies. In its announcement, Spamhaus said that the mail servers of large telecommunications providers and ISPs, which jointly generate a major proportion of the email traffic worldwide, as well as the senders of solicited bulk emails are not eligible for whitelisting. Priority treatment of such senders can be achieved via a separate whitelist that Spamhaus says is in preparation, or via a project with a wider scope such as DNSWL.
Whitelist accounts are currently only available by invitation. During the beta release phase (until December 2010), prospective whitelist users must first be sent an invitation by someone who already has a whitelist account. Whitelisting an IP address or domain which is on the blacklist is not permitted.
Technically speaking, the whitelist functions like the existing blacklist. The recipient's mail server determines the status of the sender's IP address via a DNS query. In addition to the SWL for IPv4 and IPv6 addresses, Spamhaus has set up the DWL for domains which use DKIM authentication.