Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles; site hpcnof.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!mhuxm!mhuxf!mhuxi!mhuxh!mhuxv!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!hpfcdc!hpfcla!hpcnof!dat From: dat@hpcnof.UUCP Newsgroups: net.mail.headers Subject: Mail Header Summary Document... Message-ID: <50000001@hpcnof.UUCP> Date: Fri, 11-Oct-85 12:24:00 EDT Article-I.D.: hpcnof.50000001 Posted: Fri Oct 11 12:24:00 1985 Date-Received: Thu, 17-Oct-85 01:26:15 EDT Organization: 11 Oct 85 10:24:00 MDT Lines: 426 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: 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 ". 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}.@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 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 ------------------------------------------------------------------------------