Re: How does the new anti spam SPF work regarding the senders email address ?

From: Sam (sam_at_email-scan.com)
Date: 10/17/04 

Date: Sat, 16 Oct 2004 17:44:36 -0500

Frank Callone writes:

> SPF (Sender permitted from) seems to be the neew next anti spam technology.
> But how does it treat the senders email address in the "from" header field of a mail?
>
> Is it allowed to change the from field after introduction of SPF?
> Or is only the senders IP address unchangeable ?

SPF defines how to determine what a domain thinks about the relationship
between a particular IP address, and an E-mail address in the domain in
question. All SPF implementations use this to determine whether to accept
an E-mail message originating at a particular IP address, and carrying a
particular envelope return address.

However, there's no technical barrier to substituting the envelope return
address with the address in the From: header; and checking that relationship
in addition to, or instead of, the traditional check that uses the envelope
return address. If an individual site chooses to do something like that,
it's certainly their privilege to operate their mail servers in whatever
way they see fit. And, I'm sure that quite a few organizations configure
their mail servers to do just that.

Earlier this year Microsoft proposed a validation scheme for the From:
header, that's based on SPF. Microsoft submitted their proposal to the IETF
MARID working group for standardization purposes; however Microsoft
also announced patent claims on their "Sender ID" proposal. Because
Microsoft was unwilling to use patent licensing terms that were acceptable
to the open source community, Microsoft's Sender ID proposal was ultimately
rejected.

> The problem is that on my computer there are a couple of people occasionally working
> (and sending email to our only provider).
> From this internet provider we got 1 email address (and one email account on the his server).
>
> Currently we can change the sender email address from user to user e.g.
> karl@xxxxx.com
> peter@xxxxx.com
> paul@xxxxx.com
>
> Is this possible with SPF or do we really have to buy an extra upgrade to a multi account package?

None of that has any relevance to SPF.

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