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Can someone tell me when and why a client, MTA relay, Unix .Forward, anonymous relay, or listserver will create, or alter these headers:

  • Resent-Sender:
  • Resent-From:
  • Sender:
  • From:

If you can please include a software version, or an example of software that alters any of those fields.

Finally is it correct to say that the Purported Responsible Address is "dynamic"? (see page 13 here)

makerofthings7
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1 Answers1

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The following information on message headers comes from Microsoft's information on SenderID

Resent-From

  • This is the preferred header for mailing list software to use. Also the servers that unauthenticated guests use (on a hotel network for example) should post their address here.

Sender

  • Third party mailing lists, "email this article to a friend", and similar services that send email on behalf of users use this field.

  • Most of today's mailing list software already adds a header, usually "Sender, that identifies the owner of the mailing list.

From:

  • This header is used by default when a user in one domain sends email to a user in another.

None of the above

  • Unix .forward configurations don't change anything within the email and make it impossible to distinguish from a spoofer. These systems should use the Resent-from header, or Sender header.

In addition to the headers mentioned above, Microsoft proposed a new envelope command called Mail Submitter that would work alongside the traditional Mail from command

(This is a Community Wiki Post, please edit or update with correct information as you come across it)

makerofthings7
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