Re: A Question about the pobox.com wizard

> > So, that begs the question: when it suggests the records
> >
> >   'mail.ifokr.org:v=spf1 a -all:3600
> >   'puddle155.drizzle.com:v=spf1 a -all:3600
...

> If either machine bounces a message the MAIL FROM: will be the null sender:
> '<>'.
>
> Obviously we can't do an spf lookup on that, so spf falls back onto the smtp
> HELO string, which would be "mail.ifokr.org" or "puddle155.drizzle.com".
>
> To stop spammers pretending everything they send is a bounce these hostnames
> need spf records too, the "v=spf1 a -all" just says 'any A record from
> "mail.ifokr.org" is allowed to claim to be "mail.ifokr.org" in any email
> they send'.
And voila, all my questions about SPF are answered.  I'm digging it.

--
Brian Hatch                  What do you call a firewall
   Systems and                that proxies HTTP, SMTP,
   Security Engineer          ftp, telnet, and ping?
http://www.ifokr.org/bri/    A router.

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