Re: [Asrg] What are the IPs that sends mail for a domain?
Ian Eiloart <iane@sussex.ac.uk> Tue, 30 June 2009 09:55 UTC
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Subject: Re: [Asrg] What are the IPs that sends mail for a domain?
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--On 29 June 2009 13:36:00 -0400 Bill Cole <asrg3@billmail.scconsult.com> wrote: > >> There is, actually. If you publish SPF records with a strong -all, then >> recipients can easily decide to reject (not bounce) messages. Add DKIM >> signatures, and they'll be able to tell when someone has forwarded your >> legitimate email. > > Do you have any evidence that this actually works to any detectable > degree? > > I have solid proof that it is far from perfect, but I only have a handful > of addresses that ever had significant bogus bounce flow in the one > domain I could safely use in a SPF '-all' effectiveness test. The first 5 > years of that test have shown a slow drop in the rate of bad bounces in > general offered to that domain, but it isn't much more proportionally > than the drop from a dribble to a trickle that I've seen for a domain > with no SPF record. The noise in my minuscule and weakly controlled data > makes it quantitatively worthless, but on a qualitative basis it makes > clear that strong SPF records are not yet a strong universal tool for > preventing blowback bounces. > > If you are aware of SPF being any more useful than prayer at controlling > blowback, please share it. Well, my claim is a theoretical one, and perhaps a hope for the future. It probably isn't yet effective. I do believe that it will be one day. However, I do believe that people should take SPF records into account when deciding whether to generate bounce messages. It should not be a problem if there's a positive SPF or DKIM match. You shouldn't do it if there's an SPF fail. It's harder to decide what to do in the absence of SPF, or a neutral or softfail result. I'd suggest that to drive up adoption of SPF, don't bounce for a neutral or softfail result (instead give a 5xx error), but (this will be controversial) feel free to bounce into domains that aren't trying to help - ie domains that don't publish SPF records at all. (ducks). -- Ian Eiloart IT Services, University of Sussex 01273-873148 x3148 For new support requests, see http://www.sussex.ac.uk/its/help/
- [Asrg] What are the IPs that sends mail for a dom… Franck Martin
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… SM
- Re: [Asrg] What are the IPs that sends mail for a… John Johnson
- Re: [Asrg] What are the IPs that sends mail for a… Daniel Feenberg
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Lyndon Nerenberg
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Franck Martin
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Franck Martin
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Franck Martin
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] reject and DSN, was What are the IPs John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… Seth
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Paul Russell
- Re: [Asrg] What are the IPs that sends mail for a… Jeff Macdonald
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Daniel Feenberg
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] What are the IPs that sends mail for a… Lyndon Nerenberg
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… J.D. Falk
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Rich Kulawiec
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Rich Kulawiec
- Re: [Asrg] What are the IPs that sends mail for a… Rich Kulawiec
- Re: [Asrg] What are the IPs that sends mail for a… Daniel Feenberg
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- [Asrg] Proposed corollary to Godwin's law John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… David Wilson
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… J.D. Falk
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Franck Martin
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] What are the IPs that sends mail for a… David Nicol
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] What are the IPs that sends mail for a… Paul Russell
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… der Mouse
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Gordon Peterson
- Re: [Asrg] reject and DSN, was What are the IPs John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] "Affiliation" John Leslie
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Gordon Peterson
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… Rich Kulawiec
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Seth
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] "Affiliation" Alessandro Vesely
- Re: [Asrg] reject and DSN, was What are the IPs Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] Proposed corollary to Godwin's law mathew
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Rich Kulawiec
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… John Leslie
- Re: [Asrg] What are the IPs that sends mail for a… John Leslie
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] reject and DSN, was What are the IPs Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… John Leslie
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… John Leslie
- Re: [Asrg] What are the IPs that sends mail for a… Dotzero
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] reject and DSN, was What are the IPs John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] reject and DSN, was What are the IPs Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] reject and DSN, was What are the IPs Chris Lewis
- Re: [Asrg] reject and DSN, was What are the IPs Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Steve Atkins
- Re: [Asrg] reject and DSN, was What are the IPs John Levine
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Chris Lewis
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Chris Lewis
- Re: [Asrg] What are the IPs that sends mail for a… Chris Lewis
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Bill Cole
- Re: [Asrg] What are the IPs that sends mail for a… Ian Eiloart
- Re: [Asrg] What are the IPs that sends mail for a… Alessandro Vesely
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… Peter Koch
- Re: [Asrg] What are the IPs that sends mail for a… Douglas Otis
- Re: [Asrg] What are the IPs that sends mail for a… David Nicol