Mail being sent from my domain...
fbsd06 at mlists.homeunix.com
Sat Jan 6 16:25:04 UTC 2007
On Sat, 06 Jan 2007 14:33:46 +0000
Matthew Seaman <m.seaman at infracaninophile.co.uk> 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.
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