reverse DNS; RE: [Asrg] RMX proposals and Nash Equilibrium
"Bob Atkinson" <bobatk@exchange.microsoft.com> Mon, 05 May 2003 22:32 UTC
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Subject: reverse DNS; RE: [Asrg] RMX proposals and Nash Equilibrium
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Thread-Topic: reverse DNS; RE: [Asrg] RMX proposals and Nash Equilibrium
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From: Bob Atkinson <bobatk@exchange.microsoft.com>
To: "Eric D. Williams" <eric@infobro.com>, Daniel Feenberg <feenberg@nber.org>, asrg@ietf.org
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Date: Mon, 05 May 2003 15:18:39 -0700
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Reverse DNS has two quite important situations in which it does not easily (if ever) give appropriate answers for use in spam deterrence. 1) If I host my own DNS servers, and have no DNS relationship with my ISP, then (typically, if not mostly) the rDNS lookup will ultimately go to him but have no means by which it can connect to my DNS servers and thus give a meaningful response. As a result, the rDNS lookup yields answers like dsl-209-123-212-68.myisp.com rather than something related to the email domains that I actually send from. 2) If, for one of possibly many reasons, I legitimately relay my outbound mail through some other domain, then it becomes administratively very cumbersome (if not logistically impossible, pragmatically speaking) to have the rDNS lookup resolve to something in my domain (in addition to the one through which I am relaying, and all the others he relays for). RMX-style proposals, which start their lookup at the domain purportedly responsible for a message, don't suffer from these shortcomings. (indeed, they can nicely leverage the existing administrative infrastructure that I necessarily have to mange my MX records). This is an important advantage. Ultimately, these approaches yield the same information, namely an answer to the question: "is this IP address authorized by the admin of this domain to transmit mail on behalf of that domain". While the spoofing that this prevents is VERY interesting and useful, it is, in and of itself, of course not something that will eliminate spam. Additional infrastructure is needed above and beyond RMX. Bob -----Original Message----- From: asrg-admin@ietf.org [mailto:asrg-admin@ietf.org] On Behalf Of Eric D. Williams Sent: Saturday, May 03, 2003 6:16 PM To: 'Daniel Feenberg'; asrg@ietf.org Subject: RE: [Asrg] RMX proposals and Nash Equilibrium All of these are valid points to argue, but without addressing a fundemental point (not described in most) RMX proposals from my understanding. That is, DNS can also be used to validate an IP reverse map so that not only the domain is checked but also the IP. In that case, IMHO, one could argue that an additional check for IP origination or relay of delivery would mitigate the concerns. I could definitely be wrong but that always sticks out to me as a mis-understanding of that type of proposed solution/strategy. I don't think the forwarder of mail has to be penalized for forwarding if they are properly registered in the forwarding path (open-relays are another matter in my opinion) and are no longer used in the historical context (helping a brother/sister system out). _______________________________________________ Asrg mailing list Asrg@ietf.org https://www1.ietf.org/mailman/listinfo/asrg
- reverse DNS; RE: [Asrg] RMX proposals and Nash Eq… Bob Atkinson
- RE: reverse DNS; RE: [Asrg] RMX proposals and Nas… Eric D. Williams