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On Tue, 26 Apr 2005, m. kolb wrote: > Dennis Boone <[log in to unmask]> writes: > > > This morning's "entertainment" leads me to the following question: > > > > Why doesn't mail.msu.edu add message-id headers when it receives a > > message without them? > > That doesn't make sense. The message-id is an origination mechanism. > It is our servers job to include a "Received:" on incoming messages. > Placing a Message-ID on a message we are not sending (but delivering) > just muddies up the water, and would actually be a violation of the > RFC. No. RFC2822, section 3.6.4 says that every message SHOULD (but is not absolutely required to) have a Message-ID header. Its only requirement is that it be globally unique. While it is obviously best if the originating system puts it there, and subsequent systems keep it as long as the content of the message remains the same (not counting additional Received: headers and the like), there is nothing that says that a message without such a header cannot acquire one from a later system on the path to the end user. The 'sendmail' MTA defaults to adding a Message-ID when it receives a message which lacks one (cf. pp. 544, 761 and 1118 of the 3rd edition of the O'Reilly _sendmail_ book by B. Costales and E. Allman) with the stated rationale that many MUA software packages expect to see a Message-ID header and may get confused if it is not there. > > ./muk > > -- > m. kolb <[log in to unmask]> > ------------------------------------------------------------------------- George J Perkins http://www.pa.msu.edu/people/perkins/ 1209B BPS Bldg, MSU Phone: 517-355-9200 ext 2567 East Lansing, MI 48824-2320 FAX: 517-353-4500