Re: [dmarc-ietf] tree walk and Org and PSD, Second WGLC for draft-ietf-dmarc-psd

"Chudow, Eric B CIV NSA DSAW (USA)" <> Mon, 23 November 2020 14:29 UTC

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From: "Chudow, Eric B CIV NSA DSAW (USA)" <>
To: Laura Atkins <>, "Murray S. Kucherawy" <>
Thread-Topic: [dmarc-ietf] tree walk and Org and PSD, Second WGLC for draft-ietf-dmarc-psd
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Date: Mon, 23 Nov 2020 14:28:22 +0000
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Subject: Re: [dmarc-ietf] tree walk and Org and PSD, Second WGLC for draft-ietf-dmarc-psd
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Even for .mil, the vast majority of email domains are fairly short with four or fewer labels. Most of the other ones tend to be individual servers that send automatic performance emails, and I think should be considered more of an edge case and less of our concern.


Eric Chudow

DoD Cybersecurity Mitigations

From: Laura Atkins []
Sent: Monday, November 23, 2020 8:19 AM
To: Murray S. Kucherawy
Subject: Re: [dmarc-ietf] tree walk and Org and PSD, Second WGLC for draft-ietf-dmarc-psd

On 22 Nov 2020, at 06:06, Murray S. Kucherawy <<>> wrote:

On Sat, Nov 21, 2020 at 6:23 PM John Levine <<>> wrote:
It is my impression that most real From: domains are pretty short. I
don't think I've ever seen one more than four labels long that wasn't
deliberately contrived. Anyone got data on that?

I'd bet there are some in .gov or .mil, especially the latter, but otherwise I think the longest one I've seen is five, and that was not a host that receives mail.

I'm sure we can all scrape our own mail logs for evidence either way.

This might be a place where one (or more) of the big ESPs can help. They’re going to have billions of email addresses and know which ones have MXs. I’m happy to ask for that data if it would be of use.


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