spf-discuss
[Top] [All Lists]

Re: Explain please (Was: SPF Stats)

2005-07-06 08:56:00


David Woodhouse wrote:
On Wed, 2005-07-06 at 09:22 -0600, Commerco WebMaster wrote:
<snip>

And perhaps that should be true in all cases, but those where the forwarders are known and trusted by the MTA receiving the forwarded message. After all, the receiver should logically be able to know their allowed and trusted forwarders. A sender cannot know the recipients forwarders as it just sends to the MX it finds in DNS (which for your example should be the ISP's MTA), but the final recipient's MTA certainly should.


No. Again you miss the point. The forwarding sites have nothing to do
with _either_ the sending or receiving domains.
Wrong. The forwarding site has EVERYTHING to do with the ORIGINAL receiving domain. And that's where the relationship exists, because the original receiving domain has a relationship with the final receiving domain. User of the original receiving domain is using the forwarder to define the relationship to his final receiving domain.

The admin at my ISP has
_no_ way of knowing how many of the thousands of forwarding services out
there may be forwarding to his users.
Nor does the admin at your ISP need to know. The original receiving domain knows, and needs to ensure the forwarder forwards without forgery or the original receiving domain has an SPF record that reflects forwarder does forgery (explicitly listing the forwarder, using trusted-forwarder, etc to accomodate the forgery forwarding)


It just isn't practical in the general case for a receiving site to know
the IP addresses of all the potential forwarding hosts.
Thank goodness, because the final receiving site DOESN'T need to know, only the first receiving site who is using the forwarding service needs to know.




--
Terry Fielder
terry(_at_)greatgulfhomes(_dot_)com
Associate Director Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
Fax: (416) 441-9085


<Prev in Thread] Current Thread [Next in Thread>