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emersion/mailing-lists.md

Last active February 25, 2019 11:19
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  1. emersion revised this gist Feb 25, 2019. 1 changed file with 2 additions and 1 deletion.
    3 changes: 2 additions & 1 deletion mailing-lists.md
    View file
    Original file line number Diff line number Diff line change
    @@ -9,7 +9,8 @@ address. Broadcast message with MAIL FROM set to the list's address.
    Issues:

    * Bounces don't go to the list (they should because of Sender).
    * Can't add a prefix to Subject or a footer to body.
    * Can't add a prefix to Subject or a footer to body. No unsubscribe link, is
    this GDPR-compliant?
    * Breaks DMARC alignment for SPF (but SPF is legacy). If DKIM is also used it
    should be fine, except if the DMARC policy specifies fo=1 (requires both SPF
    and DKIM to pass).
  2. emersion created this gist Feb 13, 2019.
    39 changes: 39 additions & 0 deletions mailing-lists.md
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,39 @@
    What does a mailing list need to do to reflect a message?

    Method 1
    ========

    Keep the original From header. Add a Sender header field with the list's
    address. Broadcast message with MAIL FROM set to the list's address.

    Issues:

    * Bounces don't go to the list (they should because of Sender).
    * Can't add a prefix to Subject or a footer to body.
    * Breaks DMARC alignment for SPF (but SPF is legacy). If DKIM is also used it
    should be fine, except if the DMARC policy specifies fo=1 (requires both SPF
    and DKIM to pass).

    Method 2
    ========

    Replace From with the list, add Reply-To with the original From, strip DKIM.
    Broadcast message with MAIL FROM set to the list's address.

    Issues:

    * Headers are messed up and don't make sense (From is not the real From).
    * Replies go to the list instead of the original author.

    Extra stuff
    ===========

    * Add List-* fields
    * Sign with the list's DKIM key

    References
    ==========

    * SPF RFC: https://tools.ietf.org/html/rfc7208
    * DKIM RFC: https://tools.ietf.org/html/rfc6376
    * https://begriffs.com/posts/2018-09-18-dmarc-mailing-list.html