On Thursday 20 July 2006 16:46, Robert Millan wrote:
On Thu, Jul 20, 2006 at 04:37:17PM -0400, Scott Kitterman wrote:
I would put it differently. Best guess doesn't enter into it because I
have an SPF record, but if you ran the best guess check against any
e-mail I've sent for the last 10 years, it would fail.
Did you send them from dynamic IP addresses? This used to be possible
untill recently, when every DNSBL around gets to add your IP. Now I'm
forced to route my mail through a trusted external relay.
No, I didn't run my own mail server until recently. I either sent them
through my ISP (who is a different provider than my domain host and on
completely different networks) or through my domain host's mail server. As
it happens, it's on a different IP block than their hosting servers so it
would fail best guess.
My point is that this seemingly unrelated restriction has motivated a
significant number of senders to adapt to best-guess, before best-guess
even existed :-)
To the extent that they use the same provider for hosting a domain and as an
ISP that may be the case. It isn't true for me.
(anyway, I'll keep gathering X-SPF-Guess: results for a while. so far
they're all good)
Good.
This is similar conceptually, although not nearly as draconian, as rejecting
mail that is not sent from an MX for the domain. That seems to have fallen
back out of fashion because it was trying to tie mail sending and mail
receiving to the same server and there is no requirement for that.
Best guess tries to assume that there is some relationship between the IP
address of a legitimate sending mail server and either the MX or the web
server for a domain. While this may often be true, there is no basis in
internet standards to make that type of assumption.
Good luck.
Scott K
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