Spammers Skirt IP Authentication Attempts

Fri Sep 10 07:55:55 UTC 2004

On Wed, Sep 08, 2004 at 03:15:14PM -0500,
 Robert Bonomi <bonomi at mail.r-bonomi.com> wrote 
 a message of 37 lines which said:

> Same thing applies for 'simple' forwarding via sendmails '~/.forward'
> mechanism.  the mail server 'accepts' the mail from the original source,
> and then 're-sends' to the new destination.  That re-send originates as
> the _forwarding_party_, WITH an 'envelope from' of that forwarding
> party,

Sorry, this is simply not true (sendmail, postfix, etc, always keep
the original envelope from when forwarding).

> An SPF check of the _immediate_ sender does *NOT* break forwarded
> mail.

Even SPF people say it:

http://spf.pobox.com/faq.html#forwarding