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Path: utzoo!linus!security!genrad!grkermit!masscomp!clyde!burl!hou3c!wcwells%ucbopal.CC@Berkeley.ARPA
From: wcwells%ucbopal.CC@Berkeley.ARPA
Newsgroups: net.mail.headers
Subject: Re: Several questions/comments on time zones
Message-ID: <8401302340.AA09824@ucbopal.CC.Berkeley.ARPA>
Date: Mon, 30-Jan-84 18:40:24 EST
Article-I.D.: ucbopal.8401302340.AA09824
Posted: Mon Jan 30 18:40:24 1984
Date-Received: Thu, 2-Feb-84 01:08:31 EST
Sender: ka@hou3c.UUCP (Kenneth Almquist)
Lines: 66

I believe we need to have two types of date-time stamps:  UTC (or Z)
and local. Machine readable date-time fields of messages in transit
should be in UTC to make programming easier for mail transport
programs. The senders local time stamp could be added as a comment when
message is transmitted. Simple mailers could be required to use UTC,
more complex mail programs could do local time conversion.

Here is an example of how dates could be changed when displayed to
the user and when passed to the mail transport system:

        a. Mailer/Mail composition program using local date displays:

	Date:  Sun, 29 Jan 84 10:03 EST

or
	
	Date:  Sun, 29 Jan 84 15:03 UTC (Sun, 29 Jan 84 10:03 EST)

(I prefer the latter) but transmits:

	Date:  Sun, 29 Jan 84 15:03 UTC (Sun, 29 Jan 84 10:03 EST)

to the mail transport system.

        b. Relaying and receiving hosts would use only UTC at the mail
transport level. Thus with a "received" field added the header might
become:

	Date:  Sun, 29 Jan 84 15:03 UTC (Sun, 29 Jan 84 10:03 EST)
	Received: from MIT-MC (mit-mc.ARPA) by UCB-VAX.ARPA (4.22/4.21)
		id AA00611; Sun, 29 Jan 84 17:53:41 utc

       c. The receiver (addressee) of the message should have the option
of displaying "Date" and "Resent-Date" in either the transmittted
mail transport form:

	Date:  Sun, 29 Jan 84 15:03 UTC (Sun, 29 Jan 84 10:03 EST)
	Received: from MIT-MC (mit-mc.ARPA) by UCB-VAX.ARPA (4.22/4.21)
		id AA00611; Sun, 29 Jan 84 17:53:41 utc

or with the UTC part of the "Date" and "Resent-Date" changed to the
receiver's local time:

	Date:  Sun, 29 Jan 84 07:03 PST (Sun, 29 Jan 84 10:03 EST)
	Received: from MIT-MC (mit-mc.ARPA) by UCB-VAX.ARPA (4.22/4.21)
		id AA00611; Sun, 29 Jan 84 17:53:41 utc

(Note that the "received" field date-time remains in UTC. The message
should be stored in its "mail transport form".)

	d. Referencing of the received message would use the full
date-time field:

	In-Reply-To:  Message of Sun, 29 Jan 84 15:03 UTC (Sun, 29 Jan 84 10:03 EST)
		from "Benson I. Margulies" 

The nice thing about the above scheme is that only one time zone is
used at the mail transport level and we do not have to change RFC822
to implement the above since a () comment field maybe used now with any
header field.

Bill Wells
wcwells@Berkeley.ARPA