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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: ISP phishing
On Wed, 29 Jun 2005, Mike Leber wrote: Current mobile-user arguments against SPF do indeed remind of the anti open-relay battles 5-8 years ago. Not only that but often enough itsSee my other email in regards to this mobile user strawman argument. Look in the archives for the same arguments against closing open relays. the same people who are doing this arguing ... (just look at the main ietf mail list and you'll see what I mean). Unfortunately per-user filters for SMTP transmission are notoriously difficult to implement (especially on large scale). Plus you may notIf Alice wants to forward [email protected] to [email protected] and use SPF or MX+ with [email protected] presumably she won't block email from her other account and she can check if she got it right really easy by sending email to [email protected] be able to say that email came in forwarded just from SMTP transmission (forwarders often do not leave its own marker, you can try to identify forwarder by EHLO name but that may not be forwarder by some kind of outbound relay server on the forwarding network site). Another issue is that are doing the forwarding are the ones that are most often least maintained as far as upgrading software and enabling new SMTP features. As a result an idea that we will ask all forwarders to change and identify themselves in forwarded mail can not happen as quickly as path authentication proponents want. Now I did propose one solution to this - a way to bypass forwarders by having origin mail servers add crypto signatures with their own hostname serving as base and then tie in further path authentication to cryptographically verified hostname (see paper, I previously posted, quick link at http://purl.org/NET/pacap), and I have more hope in another system that I'll get to later this year. -- William Leibzon Elan Networks [email protected]
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