On 2009-11-24, at 1:27 PM, Joel Jaeggli wrote:
Valdis.Kletnieks@vt.edu wrote:
On Tue, 24 Nov 2009 11:50:54 EST, Brad Laue said:
maintained. I'm unclear as to why mail administrators don't work more proactively with things like SenderID and SPF, as these seem to be far more maintainable in the long-run than an ever-growing list of IP address ranges.
There's a difference between maintainable and usable. Yes, letting the remote end maintain their SenderID and SPF is more scalable, and both do at least a plausible job of answering "Is this mail claiming to be from foobar.com really from foobar.com?". However, there's like 140M+ .coms now, and neither of them actually tell you what you really want to know, which is "do I want e-mail from foobar.com or not?". Especially when the spammer is often in cahoots with the DNS admins...
identify framework with trust anchors and reputation management are not things that spf or pra actually solve. spammers can publish spf and senderid records and in fact arguably have more incentive to do so if it can be demonstrated that your mail is more likely to be accepted on the basis of their existence.
True, but wouldn't a blacklist of SPF records for known spam issuing domains be a more maintainable list than an IP block whitelist? (I'm no doubt missing something very obvious with this question) Brad