On Sat, 06 Jan 2007 14:33:46 +0000 Matthew Seaman <[EMAIL PROTECTED]> wrote:
> Your reasoning is incorrect. The presence or absence of SPF records > affects how the systems that are the targets of the spam attack work, > and those are not in the control of the spammers. The ability of > a mail system to realise by analysis of SPF records that the mailer > connecting to it is an impostor that has no right to send mail from > the falsely claimed sender address means that the message can be > rejected early during the SMTP dialogue with a 5xx error (ie > permanent delivery failure) even before the body of the message has > been transmitted. > ... > Secondly, you are assuming that the software the spammers use to > inject e-mail is compliant with the various standards (RFCs 2821, > ... Delivery failures are normally generated by the sending server. If you block SPF failures at the SMTP level there are two possibilities. If the sender is a real MTA it will generate a backscatter delivery failure. If it's a spambot or spamming script then it wont, but it wouldn't have anyway, with or without SPF. SPF may help fight spam, but I don't see how it can have a major impact on backscatter when people use 5xx errors. _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"