# How Mailing Lists Break DMARC, and Why ARC Only Partly Fixes It

Page: https://stenobird.com/podcast/cybersecurity-tech-brief-by-hackernoon-6365646/how-mailing-lists-break-dmarc-and-why-arc-only-partly-fixes-it
Text version: https://stenobird.com/podcast/cybersecurity-tech-brief-by-hackernoon-6365646/how-mailing-lists-break-dmarc-and-why-arc-only-partly-fixes-it.md
Podcast: [Cybersecurity Tech Brief By HackerNoon](https://stenobird.com/podcast/cybersecurity-tech-brief-by-hackernoon-6365646)
Published: 2026-08-16T16:00:55+00:00
Episode link: https://share.transistor.fm/s/2a7f41e7
Audio file: https://media.transistor.fm/2a7f41e7/3d76961b.mp3
Processing state: not_requested
JSON: https://stenobird.com/v1/public/podcasts/cybersecurity-tech-brief-by-hackernoon-6365646/episodes/how-mailing-lists-break-dmarc-and-why-arc-only-partly-fixes-it
Duration seconds: 344

## Resource

This story was originally published on HackerNoon at: https://hackernoon.com/how-mailing-lists-break-dmarc-and-why-arc-only-partly-fixes-it . Why mailing lists break DMARC, what ARC (RFC 8617) actually does about it, why it only helps where the receiver trusts the sealer, and why From-munging is the reliable fix. Check more stories related to cybersecurity at: https://hackernoon.com/c/cybersecurity . You can also check exclusive content about #email-authentication , #dmarc , #dkim , #mailing-list-management , #email-deliverability , #dmarc-alignment , #mailing-lists-vs-dmarc , #mailing-list-security , and more. This story was written by: @vadimivanov . Learn more about this writer by checking @vadimivanov's about page, and for more stories, please visit hackernoon.com . Mailing lists break DMARC because they modify messages and forward from their own servers. ARC lets a list vouch that the message passed DMARC before it touched it, but only helps at receivers that evaluate it and trust the sealer's reputation. From-munging is the universal fix; run both.

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## Transcript

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