nanog mailing list archives
RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC
From: "Keith Medcalf" <kmedcalf () dessus com>
Date: Mon, 08 Jul 2019 19:38:03 -0600
DKIM brought nothing of any value since it cannot be used to refuse messages or abort before entering the DATA phase of the SMTP conversation. You are, no matter what, committing resources to receiving the message and accepting responsibility for its delivery. All you can do is fart about AFTER THE FACT, after it is already too late to reject the message. Presently 99.999999% of the SPAM that gets through to me is DKIM signed, yet it is still spam. In fact, that DKIM signature provides absolutely nothing of value whatsoever, except to validate that the SPAM was unmolested between the sending MTA and me (which is unlikely anyway, and even more unlikely since the transport is almost always over a TLS channel which prevents tampering between the sending MTA and my MTA anyway). Like I said, DKIM does nothing of value and is directed to solve a problem that does not, never has, and never will, exist in the real world. Contrast this with SPF which does do something of value. It enables the dropping of the session BEFORE the DATA phase if the envelope-from domain is not on the list of authorized MTA to be sending messages for that domain. The only real problem with it is the allowance of prevarication in the data. -- The fact that there's a Highway to Hell but only a Stairway to Heaven says a lot about anticipated traffic volume.
-----Original Message----- From: Michael Thomas [mailto:mike () fresheez com] On Behalf Of Michael Thomas Sent: Monday, 8 July, 2019 19:24 To: Valdis Klētnieks Cc: Keith Medcalf; nanog () nanog org Subject: Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC On 7/8/19 6:11 PM, Valdis Klētnieks wrote:On Mon, 08 Jul 2019 17:58:17 -0700, Michael Thomas said:On 7/8/19 5:54 PM, Keith Medcalf wrote:This is because DKIM was a solution to a problem that did notexist.::eyeroll:: pray tell, how do you "always" know the identity ofthe MTAsending you a message?It's more subtle than that - you always know the "identity" of thepurportedMTA, because you know their IP address. Whether "purported" is thesame as"legitimate" or "authorized" is a whole different kettle offish....Remember - port 25 is widely blocked precisely because there werealways aplenty supply of MTAs whose identity you knew, sending you spamfrom consumerliving rooms....Like I said, what DKIM brought is the ability to "blame me". knowing the IP address doesn't give you that in any useful way. Recall that trust is mainly a social construct, not a technical one. Bruce Schneier has written about that endlessly. Mike
Current thread:
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC, (continued)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Michael Thomas (Jul 08)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Keith Medcalf (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Michael Thomas (Jul 08)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Keith Medcalf (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Christopher Morrow (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Michael Thomas (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Izzy Goldstein - TeleGo (Jul 09)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Michael Thomas (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Valdis Klētnieks (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Michael Thomas (Jul 08)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Keith Medcalf (Jul 08)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Rich Kulawiec (Jul 10)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Peter Beckman (Jul 10)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Sean Donelan (Jul 10)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Christopher Morrow (Jul 10)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Keith Medcalf (Jul 10)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Paul Timmins (Jul 11)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Brian J. Murrell (Jul 11)
- Re: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Christopher Morrow (Jul 11)
- RE: SHAKEN/STIR Robocall Summit - July 11 2019 at FCC Keith Medcalf (Jul 11)