On 1 Jan 2018, at 09:41, Matus UHLAR - fantomas <uh...@fantomas.sk> wrote: > the gross format in RFCs 822,2822 and 5322 describes message-id consisting > of local and domain part,
You are misreading the RFC. The Message-ID itself is a *should* and there is no MUST un any of the description of the construction of the Message-ID, only that it MUST be globally unique. 5322 specifically states: "Though other algorithms will work, it is RECOMMENDED that the right-hand side contain some domain identifier (either of the host itself or otherwise) such that the generator of the message identifier can guarantee the uniqueness of the left-hand side within the scope of that domain." There is no requirement to include a local and domain part in any part of a Message-ID. A 256-bit would be unique to some significant fraction of the atoms in the universe. I'd posit that meets any reasonable definition of "must be globally unique." But, in practice, the simplest way to guarantee uniqueness is to generate a timestamp and add it to a domain/IP/local ID. -- "We take off our Republican hats and put on our American hats" -- Many Republicans in Sep 2008
