On Fri, 2005-03-18 at 13:18, Scott Kitterman wrote:
Generally speaking I submit it to either the ESP MTA or the "local" one
depending on my impressions of how the two are performing. I'm not blocked
either for port 25 or 587, so reaching the ESP mail server isn't a problem.
No system is perfect, but both my DSL provider and my ESP have pretty
reliable mail servers.
Okay, then this is where I was confused. You originally said "To the
extent that ESP has 100% uptime, you are right" -- I thought you were
talking specifically about your situation and reliability of your
providers, especially the way your described your redundant connections
and how email is important to your business. If someone has close to
100% uptime, then reliability, and redundancy email transmission routes,
may be less important in that situation.
My point is more that there is more than one way to get the kind of
email reliability one may want, without having to use nested includes
and complexity in an SPF record. Yes, this may mean people may have to
do things differently than they have in the past. It's a strange, new,
hopefully forgery-free, world ahead. If one has a complex system of ESP
usage, and SPF processing reaches predefined limits, it may be time to
simply your setup, rather than waiting for your upstream providers to
simply their records (and maybe their network topology) that you are
If not being forged isn't important to you or your business, then don't
publish SPF records.
What would make you believe that's the case?
Heh, this one part was meant in the general sense, not specifically
about your situation.
All I said was that it's
reasonable to want redundancy in your permitted senders.
I agree. It is reasonable. But it is also reasonable to expect big
providers to, if they are publishing, give accurate and exact SPF
records and describe their entire email sending infrastructure. This
may mean large, complex SPF records. People should do what they can to
work together and make it easier on each other (ISPs providing as
succinct records as possible, for example, or simplifying their network
layout), but in some cases this may not be possible if the services that
the ISP provides are wide ranging or complex or reliable, which may
require more complexity and length to describe.
Andy Bakun <spf(_at_)leave-it-to-grace(_dot_)com>