[iyonix-support] Re: Spam infiltration

In article <299bbf4d4e.peter@xxxxxxxxxxxxxxxxxxxxxxxxx>,
   Peter Bell <peter@xxxxxxxxxxxxxxxxx> wrote:
> In message <4e4daa8653Jeremy@xxxxxxxxxxxxxxxx>
>           Jeremy C B Nicoll <Jeremy@xxxxxxxxxxxxxxxx> wrote:

> > Some ISPs, not all of them though, copy the info that was in the
> > SMTP envelope to a fake header and include it in the mail.
> > Generally that's an "Envelope-To:" header.  But not all ISPs do
> > that.

> This info is, presumably, the same as appears after the 'for' in each
> 'Received:' header.

I'm not sure; if the mail has been forwarded at some point then I think
some of the earlier received headers will show the original intended
recipient then after the rewrite the later intended recipient.

A mail like ones on this list have "Received: ... for" values that (not
surprisingly) describe the list itself in the earlier headers and
individual recipients later (ie in headers nearer the top of the mail)
on.

Also, from a filtering pov, there's the problem that the "for" might
not be on the same line as the recipient address; "received:" headers
get spread across multiple lines.

-- 
Jeremy C B Nicoll, Edinburgh, Scotland - my opinions are my own.
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