Why doesn spamdyke filter using Sender Policy Framework (SPF), Sender ID, Certified Server Validation (CSV), DomainKeys or DomainKeys Identified Mail (DKIM)?
Each of those systems is very complex, so adding support to spamdyke will not be a small task. They’re also all different, so supporting all of them would be a major undertaking. At this point, there are other ways to improve spamdyke that will take less effort and provide much more benefit. Additionally, I’m not convinced any of those systems will make any difference. They were each designed to prevent spam being sent from forged addreses so, for example, you won’t get spam from president@whitehouse.gov. However, most spammers own their domains (often many thousands of them) and control their own DNS, so they can (and do) add SPF/CSV/etc records so their spam follows the SPF/CSV/etc rules. (Hint: Spammers understand and administer their DNS records better than most ISPs do.) The major ISPs (AOL, Yahoo!, GMail) use these systems and still have spam problems; this is pretty good evidence they aren’t living up to the hype. There is a (small) chance these systems could stop spam coming fr
