From: Victor Duchovni (no email)
Date: Mon Apr 16 2007 - 10:51:42 EDT

  • Next message: Noel Jones: "Re: Empty MAIL FROM"

    On Mon, Apr 16, 2007 at 04:38:23PM +0200, mouss wrote:

    > so, I've never seen it block spam, but it has been reported to block
    > legitmate mail. and from a standard perspective, nothing prohibits a
    > multi-recipient mail with a null sender.

    Three plausible ways in this types of mail can be legitimate:

        - Legitimate bulk-mail sending software uses <> instead of DSN
        NOTIFY=NEVER to suppress bounces (the DSN approach is not always
        effective). In most cases the sending software *should* be handling
        bounces to aid with list management.

        - Legitimate bulk-lmail sending software uses DSN NOTIFY=NEVER, but
        an intermediate DSN capable relay replaces the envelope sender with
        <> when forwarding to a non-DSN relay. Again bulk-mail should not
        ignore or discourage bounces.

        - Actual bounces returning to the responsible party are delivered
        to a group mailbox, and forwarded to the members of the group. This
        type of mail appears from outside your domain, when some of your
        users collectively own/manage an external mailbox.

    In most cases any collateral damage from filtering multi-recipient bounces
    should be low. Whether there is any benefit to blocking this type of mail
    is less clear.

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  • Next message: Noel Jones: "Re: Empty MAIL FROM"

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