🚀 go-pugleaf

	This note is to solicit information on improving the following 
document.  Thanks!

				-- Dave Taylor
				..ihnp4!hpfcla!d_taylor
				..hplabs!hpcnof!dat

-----------------------------------------------------------------------------

			 Summary of Network Mail Headers
			 -------------------------------

				   Dave	Taylor

		   Hewlett Packard, Colorado Networks Operation

			Last Revision: October 11th, 1985

	    This document contains an exhaustive description of	each of	the
       possible	 mail  headers	from  electronic  messages sent/received or
       shipped through any  of	the  following	networks:   USENET  (uucp),
       ARPANET,	BITNET,	and CSNET.

       While every effort has been made	to make	this list  complete,  there
       are  still some headers that are	not included.  If any errors, inac-
       curacies	or omissions are found,	please mail the	information includ-
       ing   a	 sample	  header   to	me   at	  ihnp4!hpfcla!d_taylor	 or
       hplabs!hpcnou!d_taylor.



                (This list is ordered more or less alphabetically)



       1.  Apparently-To:

	    This header	indicates that the message is destined to a network
       that  does  not	do address verification.  For example, if a message
       were sent from ARPA to a	non-ARPA address, it would have	this header
       included.

       Example:

	 Apparently-To:	<hplabs!hpfcla!d_taylor@HEWLETT-PACKARD.COM>

       2.  Bcc:

	    This is used by the	sender of the message to have copies of	the
       message	go to people without the 'main'	adressees knowing about	it.
       They are	the "lowest" of	the three groups of people who can  receive
       a  message  (This  is  like giving a Xerox (tm) of your memo to your
       office mate...)

       Example:

	 Bcc: jack@NLM-VAX, my_boss

       3. Cc:

	    This header	indicates whom the secondary recpients of the  mes-
       sage  are.  These people	will receive copies of the message, but	not
       via directl addressing. (This is	similar	to the carbon-copies  func-
       tion on a standard office memo).

       Example:

	 Cc: hplabs!hpcnof!d_taylor, joe@HARVARD.EDU

       4.  Comments:

	    This is for	the addition of	arbitrary text in the header of	 an
       outgoing	message.

       Example:

	 Comments: This	mail was generated by a	test version of	mailit,
		   a new program that does inter-domain	host verification
		   using psychic communications.  If it	doesn't	get the
		   mail	to you - you'll	feel a slight chill...

       5.  Date:

	    The	date and time the message was sent (or the  date  and  time
       that the	message	hit the	first 'intelligent' mailer - which will	add
       this field if it	isn't present).

       Example:

	 Date: Fri, Jan	19, 1985 12:04 MST

       6.  Encrypted:

	    This header	is for the sending and receiving of encrypted mail,
       and (usually) indicates the encryption program used.  It	can option-
       ally include a public key encryption key	(which,	by itself, is  use-
       less).

       Example:

	 Encrypted: public-encode, SECUREMAIL


       7.  From

	    The	From line where	From isn't followed by a colon is added	 by
       the  receiving  mail  system and	simply indicates what time the mail
       was received.  If the mail was sent by someone else on the same sys-
       tem,  the second	field will indicate their username, otherwise it is
       essentially useless information.

       Example:

	 From dat Wed Aug 7 1985 00:04:03 MST

       8.  From:

	    This From line is generated	by the	senders	 mail  system,	and
       will  usually  indicate not only	the address the	message	took to	get
       there, but also has the full name of  the  sender.   Sometimes  this
       header  will  be	 generated by a	mailer en-route, in which case only
       the address will	be present.  "Smartmailers"  (mail  transport  sys-
       tems)  update  the  address  on	the From: line as it passes through
       their machine...

       Example:

	 From: ihnp4!dartvax!eddy (Eddy	Van Halen)

       9.  >From

	    Certain mailers (the 'un-smartmailers') don't update the  From:
       line  and  in fact do absolutely	the minimum needed to indicate pas-
       sage of the message.  This includes simply rewriting the	"From" line
       (see the	first "From" header above) by prefixing	it with	a '>' char-
       acter and appending "remote from	<hostname>".

       Example:

	 >From uucp Wed	Sep 25 03:40:09	1985  remote from veeger

       10.  In-Reply-To:

	    This header	is generated when a message is a direct	response to
       another	message	and can	have two forms;	either using the Message-Id
       or actually using the From: line	and the	Date: line.  The  following
       is an example of	the latter form...

       Example:

	 In-Reply-To: Message from "wrap@AMES (Joe Wrap)" of 12	Sep 85 20:37:01	EDT

       11.  Keywords:

	    This is used to indicate keywords or phrases to help categorize
       the incoming message.  It is generated by the sender...

       Example:

	 Keywords: mail, electronic communications, standards, addressing

       12.  Message-Id:

	    This is a unique message identification number and is generated
       by the sending mailer.  The format for the id number is (usually):

	  YYMMDDHHMM{SS}.<message-number>@hostname{domain(s)}

       For example, if a message is sent by someone at MIT-LAB on  the	6th
       of August 1985 at 9:02:03 am, the message id would be:

	 Message-Id: <850806090203.xxxx@MIT-LAB.EDU.ARPA>

       Also, if	the sender doesn't generate this  header,  a  'smartmailer'
       along the way will include one relative to that machine.

       Example:

	 Message-Id: <8502040302.42432@HP.COM.ARPA>

       13.  Posted-Date:

	    This is a permutation of the "Date:" field.	 See "Date:".

       Example:

	 Posted-Date: Mon, 12 Aug 85 23:30:46 pdt


       14.  Received:

	    This is added by each mail transport system	relaying  the  mes-
       sage.  It indicates sending and receiving hosts and the current date
       and time	at that	point.	Oftentimes, this header	will also include a
       unique message identification number for	tracking purposes.

       Examples:

	 Received: by HP-VENUS id AA00541; Mon,	7 Oct 85 10:29:09 pdt

	 Received: from	CMU-CS by UCB-VAX.ARPA (4.24/5.3)

       15.  References:

	    This is used to indicate a referenced article  or  message	(as
       opposed to "replying to"	a message).  Most commonly, this is used in
       conjunction with	notes or news (electronic conferencing systems)	 to
       indicate	mail in	reference to a specified article or posting.

       Example:

	 References: Your posting in net.mail (hpcnoe.302) of 4	Jan, 85

       16.  Reply-To:

	    This indicates a return address for	the receiver if	they desire
       to  respond  to	the  message.  This address superscedes	the address
       generated  (en-route) on	the "From:" line.  Most	commonly,  this	 is
       used  by	 an  individual	mailing	for a group so that any	response to
       the individual will go to the group instead.

       Example:

	 Reply-To: HUMAN-NETS@RUTGERS

       17.  Resent-

	    When someone forwards  mail	 to  a	third  party  the  original
       headers	will  be  prepended with "Resent-" to preserve the informa-
       tion. The headers that currently	are allowed to be prefixed in  this
       manner are:

	 Resent-Bcc:
	 Resent-Date:
	 Resent-From:
	 Resent-Message-ID:
	 Resent-Reply-To:
	 Resent-Sender
	 Resent-To:
	 Resent-cc:

       Each field is documented	elsewhere herein.

       18.  Return-Path:

	    This header	is added at message recption by	the mail  transport
       system and is intended to indicate the return address of	the sender.
       This is superceded by 'Reply-To:' for responses,	if it's	present.

       Example:

	 Return-Path: basic!doug@uw-july

       19.  Sender:

	    This is used when the person originating the  message  is  dif-
       ferent  from  the person	actually sending the message.  For example,
       if I have a  secretary,	my  mail  could	 be  "From:"  me,  but	the
       "Sender:" would be my secretary.

       Example:

	 Sender: hplabs!STEFAN@USC-ECL

       20.  Sent:

	    A variation	of the "Date:" field.

       Example:

	 Sent: Friday, June 28th 1985 at 3:19 pm

       21.  Subject:

	    This indicates, in one line	usually, a  summarized	subject	 of
       the message.

       Example:

	 Subject: thoughts on your proposal...

       22.  To:

	    Indicates the person  or  persons  that  the  mail	message	 is
       directly	 addressed  to (as opposed to 'cc:' and	'bcc:' above).	The
       list of names may appear	on an arbitrary	number of lines.

       Example:

	 To: Dave Taylor <hpcnou!dat%hplabs.csnet@CSNET-RELAY>

       23.  Via:

	    Usually indicative of a gateway transition,	this  is  added	 by
       the gateway software transitioning from one network to another.	The
       example below is	from a message sent from the CSNET to the Usenet..

       Example:

	 Via:  CSNet; 18 Sep 85	14:26-PDT



			Extensions and User Defined Fields
			----------------------------------

       There are many more headers that	can be	found  in  electronic  mail
       (some  of which are listed below) and often the personal	headers	are
       prefixed	by "X-", since it is guaranteed	that any extensions to	the
       mail headers will not begin with	these two letters.

       It is important to note that this section is by no means	complete  -
       there  are  a  great number of strange headers floating about.  I've
       tried to	document the most common and most interesting ones here.

       24.  Latitude:

	    This header	indicates  the	relative  Latitude  and	 Longtitude
       (geographic  location)  of the sender.  Theoretically, if you have a
       "Great Circle" program, you could feed it these entries and your	own
       location	 and  figure  out  how far away	from you they are.  It's of
       dubious use, though.

       Example:

         Latitude: 40.4166       Longitude:      86.9166

       25.  Organization:

	    This is a quite  common  header  (with  it's  European  variant
       "Organisation:")	 and  indicates	 the  organization  that the sender
       works for or is attending (in the case of a University).

       Examples:

       Organisation: the Antelope project, Kruislaan 312, Amsterdam

       Organization: Hewlett Packard, Colorado Networks	Operation

       26.  Origin:

	    This is mostly used	to verify  that	 the  sending  username	 is
       actually	the person who sent it.	 it contains the tty device sending
       the message, the	hostname of the	machine	and the	date sent.

       Example:

	 Origin: tty613	on hpccc; Mon, 23 Sep 85 09:48:38 PDT

       27.  Phase-Of-The-Moon:

	    This is a strangely	popular	header that is presumed	to indicate
       what phase the moon is in at the	senders' site...more dubious infor-
       mation!

       Example:

	 Phase-Of-The-Moon: Waning Crescent (18% of Full)

       28.  Phone:

	    The	telephone number by which the sender can be  reached  (usu-
       ally their work phone number).

       Example:

	 Phone:	+31 20 5924122,	+31 20 947183


       29.  Postal-Address:

	    The	"overland" (non-electronic) mail address for the sender	 of
       the message.

       Example:

       Postal-Address: Dave Taylor,
		       HP Colorado Networks,
		       3404 East Harmony Road
		       Fort Collins, Colorado
		       80525

       30.  Sunrise:

	    What time sunrise and sunset are at	the senders location.

       Example:

	 Sunrise: 6:23	       Sunset:	19:08	(CST)

       31.  Telephone:

	    This is the	same as	'Phone:' above.

       Example:

	 Telephone: (415) 857-5875

       32.  X-Location:

	    This is the	geographic location of the sender.

       Example:

	 X-Location: Fort Collins, Colorado, USA

       33.  X-Mailer:

	    This indicates what	mailer the sender used to compose and actu-
       ally  transmit  the  message.   It's  usually  used to indicate non-
       standard	mailers...

       Example:

	 X-Mailer: fastmail [version 1.0]

       34.  X-Sent-By-Nmail-Version:

	    This is the	same as	the  "X-Mailer:"  header,  only	 much  more
       specific.  It should, in	fact, be absorbed into the previous header.

       Example:

	 X-Sent-By-Nmail-Version: 04-Nov-84 17:14:46
------------------------------------------------------------------------------