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RFC 2369 / MAILING LIST COMMANDS

Give each list command its own field

01

Six optional email fields describe list operations using URLs: Uniform Resource Locators that identify a resource or command.

DIAGRAMRead RFC section 3 ↗
RFC 2369 · § 3EXAMPLE
3 / 3
Give each list command its own fieldThree field-role views. Help, Subscribe and Unsubscribe supply the core instructions, join and leave operations. A second group distinguishes Post submission, Owner human contact and Archive access. A separate non-posting-list example uses List-Post NO and stops before any posting destination. NO is not a URL or a general-purpose value for every list field. The optional fields are generated only by list software, with at most one of each per message.Each command has a distinct fieldList-Post: NOsend a postNo posting destinationNO is a List-Post-specific exception
03
Represent a list that cannot accept posts.

Separate example: List-Post: NO signals a non-posting list. It is not a URL and must not be treated as a posting destination. No comparable NO exception is specified for List-Help.

Source for this drawing: RFC 2369 · Read RFC section 3 ↗

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Mail transport moves a message between servers. The message format describes its contents. Authentication adds checks; it does not make every message safe.

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RFC 5322 Email message format RFC 2919 Mailing list identity RFC 6068 mailto links

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KEY POINT

A command URL describes how to act; a List-Id merely names a list.

  • Core fields: List-Help obtains instructions, List-Subscribe requests addition, and List-Unsubscribe requests removal. Implemented fields SHOULD appear on all list-distributed messages, including command replies.
  • List-Post describes posting, possibly via a moderator. List-Owner contacts a human administrator; it may be omitted when that person is the mail system postmaster. List-Archive gives archive access.
  • There MUST be no more than one of each field per message, and these fields MUST be generated only by mailing lists, not end users. For a non-posting list, List-Post may contain the special value NO.
DETAILS

A list may implement only a subset; List-Help alone is acceptable and SHOULD lead to complete instructions. Distinct headers avoid inventing one new command language. List-Id is defined separately by RFC2919. NO is a List-Post exception, not a universal value for the other fields.

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