--On July 28, 2006 12:04:56 PM +0100 james <james@stev.org> wrote:
I understand the above ok. But what the problem with the server that handles the initial MX records doing the spf filtering and the end server configured in such a way that it understand not todo SPF filter from that forwarding server after all its running you mail which in my words your already "trusting" it. IT does increase the configuration overheads slightly.
You assume that they control this other mail server receiving their mail, they don't. Further we have thousands of customers per MXer, and not all of them probably would fit that 'trust' label anyway. Many of our customers forward to commercial services like GMail, Hotmail, AOL, and Earthlink. They're not going to maintain such silly configurations for their customers, neither will I. It would be completely broken and un-maintainable, customers have this habit of not informing you when they move domains or change their configurations. Heck enough of a percentage of people don't even understand that you ask for service to be cancelled, they just start swinging chargebacks at us.
I guess the same also exists for multiple MX sites when the backup server send mail to the primary MX server.
Very few places have 'normal' backup MXes anymore, the backup must have the same policies, and user lists as the primary, or it's a SPAM vector. Nowadays all MXes have to be under the same administrative control to work correctly without opening up a SPAM and/or open relay to you.