On Wed, 21 Jul 2004, Stuart D. Gathman wrote:
On Wed, 21 Jul 2004 terry(_at_)ashtonwoodshomes(_dot_)com wrote:
Consider BIGISP.com, they have 1 mail server mail.bigisp.com
Little company abc.com buys a DSL account from bigisp.com, and they setup
their email to relay through mail.bigisp.com, and abc.com's spf record
indicates mail.bigisp.com is the only mail server abc.com email comes from.
The SPF record should look like this:
v=spf1 ?a:mail.bigisp.com -all
This marks mail.bigisp.com as the only mail server abc.com email could
possibly come from.
I should add that if instead of bigisp.com, you use really-with-it-isp.com,
who requires all subscribers to use SMTP AUTH to relay mail, and checks
that the envelope from matches a list registered with the account,
and publishes this guarantee (subject to best effort of course), then
you might be justified in changing the '?' to '+' if you were a home
user.
I should also add, that for $15 a month extra, cox.net will give you
a static IP, an AUP that lets you run your own mail server, and
will unblock outgoing port 25 on request. Other ISPs have something similar.
So there is really nothing stopping a home business, or a home user with
$15/mo to spend, from sending mail that will get an SPF PASS.