On Sun, Jan 08, 2023 at 09:23:52PM +0100, Benny Pedersen wrote: > > I want again to state that header which says "Received: by > > <hostname> (Postfix, from userid <userid>)" is perfectly normal and > > expected Postfix behavior when mail is submitted locally. I have > > seen it countless number of times. > > maybe there is a valid reason postfix have 2 header formats ?
Postfix has one "Received" header format, which is the one defined in RFC5021: https://www.rfc-editor.org/rfc/rfc5321#page-60 This format has various optional elements, not all of which are applicable to every message. Postfix adds the required and reasonably applicable elements. The specification also permits unstructured comments (CFWS) between the various elements, this often include things like an IP address or string form of a timezone, etc. Any software that mandates non-required optional elements or particular content in comments is not portable. Any such expectations need to be configurable on a case-by-case basis, limited to processing messages generated in a known context that are then sure to include the expected elements. -- Viktor.
