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rfc:rfc1528

Network Working Group C. Malamud Request for Comments: 1528 Internet Multicasting Service Obsoletes: 1486 M. Rose Category: Experimental Dover Beach Consulting, Inc.

                                                          October 1993
         Principles of Operation for the TPC.INT Subdomain:
              Remote Printing -- Technical Procedures

Status of this Memo

 This memo defines an Experimental Protocol for the Internet
 community.  It does not specify an Internet standard.  Discussion and
 suggestions for improvement are requested.  Please refer to the
 current edition of the "Internet Official Protocol Standards" for the
 standardization state and status of this protocol.  Distribution of
 this memo is unlimited.

Table of Contents

 1. Introduction ..........................................   2
 2. Naming, Addressing, and Routing .......................   2
 2.1 Addressing ...........................................   2
 2.2 Routing ..............................................   3
 3. Procedure .............................................   3
 3.1 Content-Types ........................................   4
 3.2 Generating a Cover-Sheet .............................   4
 3.3 Return Receipt .......................................   6
 4. Usage Examples ........................................   6
 4.1 Explicit Cover Sheet .................................   6
 4.2 Implicit Cover Sheet .................................   7
 4.3 Minimal, Text-only ...................................   7
 5. Prototype Implementation ..............................   7
 6. Future Issues .........................................   9
 7. Security Considerations ...............................   9
 8. Acknowledgements ......................................   9
 9. References ............................................   9
 10. Authors' Addresses ..................................   10
 A. The application/remote-printing Content-Type .........   11
 B. The image/tiff Content-Type ..........................   12

1. Introduction

 Although electronic mail is preferable as a means of third-party
 communication, in some cases it may be necessary to print
 information, in hard-copy form, at a remote location.  The remote
 output device may consist of a standard line printer, a printer with

Malamud & Rose [Page 1] RFC 1528 Remote Printing – Technical Procedures October 1993

 multiple fonts and faces, a printer that can reproduce graphics, or a
 facsimile device.  Remote output may be accompanied by information
 that identifies the intended recipient.  This memo describes a
 technique for "remote printing" using the Internet mail
 infrastructure.  In particular, this memo focuses on the case in
 which remote printers are connected to the international telephone
 network.

2. Naming, Addressing, and Routing

 A printer is identified by a telephone number which corresponds to a
 G3-facsimile device connected to the international telephone network,
 e.g.,
    +1 415 968 2510
 where "+1" indicates the IDDD country code, and the remaining string
 is a telephone number within that country.

2.1 Addressing

 This number is used to construct the address of a remote printer
 server, which forms the recipient address for the message, e.g.,
 either
    remote-printer@0.1.5.2.8.6.9.5.1.4.1.tpc.int
    or
    remote-printer.ATOM@0.1.5.2.8.6.9.5.1.4.1.tpc.int
 where "ATOM" is an (optional) RFC 822 atom [1], an opaque string for
 use in recipient identification when generating a cover-sheet, and
 the domain-part is constructed by reversing the telephone number,
 converting each digit to a domain-label, and being placed under
 "tpc.int."

Malamud & Rose [Page 2] RFC 1528 Remote Printing – Technical Procedures October 1993

 Note that the mailbox syntax is purposefully restricted in the
 interests of pragmatism.  To paraphrase RFC 822, an atom is defined
 as:
    atom    = 1*atomchar
    atomchar=  <any upper or lowercase alphabetic character
               (A-Z a-z)>
              / <any digit (0-9)>
              / "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+"
              / "-" / "/" / "=" / "?" / "^" / "_" / "`" / "{"
              / "|" / "}" / "~"
 Finally, note that some Internet mail software (especially gateways
 from outside the Internet) impose stringent limitations on the size
 of a mailbox-string.  Thus, originating user agents should take care
 in limiting the local-part to no more than 70 or so characters.

2.2 Routing

 The message is routed in exactly the same fashion as all other
 electronic mail, i.e., using the MX algorithm [2].  Since a remote
 printer server might be able to access many printers, the wildcarding
 facilities of the DNS [3,4] are used accordingly.  For example, if a
 remote printer server residing at "dbc.mtview.ca.us" was willing to
 access any printer with a telephone number prefix of
    +1 415 968
 then this resource record might be present
  • .8.6.9.5.1.4.1.tpc.int. IN MX 10 dbc.mtview.ca.us.
 Naturally, if several remote printer servers were willing to access
 any printer in that prefix, multiple MX resource records would be
 present.
 It should be noted that the presence of a wildcard RR which matches a
 remote printer server's address does not imply that the corresponding
 telephone number is valid, or, if valid, that a G3-facsimile device
 is connected at the phone number.

3. Procedure

 When information is to be remotely printed, the user application
 constructs an RFC 822 message, containing a "Message-ID" field.

Malamud & Rose [Page 3] RFC 1528 Remote Printing – Technical Procedures October 1993

 If the local-part of the address does not contain an opaque string
 for use in recipient identification, then the body must consist
 "multipart/mixed" content [5] having at two parts, the first being a
 "application/remote-printing" content-type (defined in Appendix A),
 which will be used to generate a cover-sheet, and the second being an
 arbitrary content-type corresponding to the information to be
 printed.  If the local-part of the address does contain an opaque
 string for use in recipient identification, then the body consists of
 an arbitrary content-type corresponding to the information to be
 printed.
 Regardless, the message is then sent to the remote printer server's
 electronic mail address.

3.1 Content-Types

 It should be noted that not all content-types have a natural printing
 representation, e.g., an "audio" or "video" content.  For this
 reason, the second part of the "multipart/mixed" content should be
 one of the following:
 text/plain, message/rfc822, application/postscript image/tiff
 (defined in Appendix B), any multipart.
 Note that:
    (1) With the "text/plain" content-type, not all character
        sets may be available for printing.
    (2) With the "message" content-type, the subordinate content
        will be processed recursively.
    (3) With the "application/postscript" content-type, the
        remote printer server should evaluate the contents in a
        safe execution environment.
    (4) With the "multipart" content-type the subordinate contents
        will be processed recursively: for a "multipart/mixed" or
        "multipart/digest" content, each subordinate content will
        start on a new page, whilst for a "multipart/parallel" content,
        all subordinate contents will, if possible, start on the same
        page.  Naturally, when processing a "multipart/alternative"
        content, only one subordinate content will be printed.

3.2 Generating a Cover-Sheet

 If the "application/remote-printing" content-type is present,
 this contains all the information necessary to generate a

Malamud & Rose [Page 4] RFC 1528 Remote Printing – Technical Procedures October 1993

 cover-sheet.  Otherwise, the cover-sheet must be generated
 based on other information available.
 Typically, a cover sheet consists of three sections:
    o information identifying the originator;
    o information identifying the recipient; and,
    o additional information supplied by the remote printer
      server.
 To identify the originator, the remote printer server will use the
 message headers, usually by stripping any trace headers (i.e.,
 "Received" and "Return-Path") and then re-ordering the remaining
 headers starting with the "From" header.
 To identify the recipient, the opaque string from the local- part of
 the remote printer server's address is consulted.  For example, if
 the remote printer server's address is
 remote-printer.Arlington_Hewes/Room_403@0.1.5.2.8.6.9.5.1.4.1.tpc.int
 then the opaque string
 Arlington_Hewes/Room_403
 is consulted.  lp When generating a cover-sheet using this opaque
 string, the remote printer server will interpret an underscore
 character ("_") as a space, and a solidus character ("/") as an end-
 of-line sequence.  A remote printer server will interpret two
 consecutive underscore characters in the opaque string as a single
 underscore, and two consecutive solidus characters as a single
 solidus.  So, the opaque string,
    Arlington_Hewes/Room_403
    might appear on the cover-sheet as
    To: Arlington Hewes
    Room 403

Malamud & Rose [Page 5] RFC 1528 Remote Printing – Technical Procedures October 1993

3.3 Return Receipt

 When the remote printer server finishes its processing, a message is
 returned to the originator, indicating either success (i.e., the
 message was successfully sent to the facsimile device), or failure,
 with an explanation (e.g., after several repeated attempts, there was
 no answer).

4. Usage Examples

4.1 Explicit Cover Sheet

 To: remote-printer@0.1.5.2.8.6.9.5.1.4.1.tpc.int
 From: Carl Malamud <carl@malamud.com>
 Date: Thu, 22 Jul 1993 08:38:00 -0800
 Subject: First example
 Message-ID: <19930722163800.1@malamud.com>
 MIME-Version: 1.0
 Content-Type: multipart/mixed;
         boundary="----- =_aaaaaaaaaa0"
  1. —— =_aaaaaaaaaa0

Content-Type: application/remote-printing

 Recipient:    Arlington Hewes
 Telephone:    +1 415 968 1052
 Facsimile:    +1 415 968 2510
 Originator:   Carl Malamud
 Organization: Internet Multicasting Service
 Address:      Suite 1155, The National Press Building
               Washington, DC 20045
               US
 Telephone:    +1 202 628 2044
 Facsimile:    +1 202 628 2042
 EMail:        carl@malamud.com
 Any text appearing here would go on the cover-sheet.
  1. —— =_aaaaaaaaaa0

Content-Type: text/plain; charset="us-ascii"

  Here are my comments...
  1. —— =_aaaaaaaaaa0–

Malamud & Rose [Page 6] RFC 1528 Remote Printing – Technical Procedures October 1993

4.2 Implicit Cover Sheet

To:remote-printer.Arlington_Hewes/Room_403@0.1.5.2.8.6.9.5.1.4.1.tpc.int cc: Marshall Rose mrose@dbc.mtview.ca.us From: Carl Malamud carl@malamud.com Date: Thu, 22 Jul 1993 08:38:00 -0800 Subject: Second example Message-ID: 19930722163800.2@malamud.com MIME-Version: 1.0 Content-Type: application/postscript

%!

Note that in this latter example, both remote printing and e-mail recipients can be identified in the same message.

4.3 Minimal, Text-only

To:remote-printer.Arlington_Hewes/Room_403@0.1.5.2.8.6.9.5.1.4.1.tpc.int cc: Marshall Rose mrose@dbc.mtview.ca.us From: Carl Malamud carl@malamud.com Date: Thu, 22 Jul 1993 08:38:00 -0800 Subject: Third example Message-ID: 19930722163800.3@malamud.com

Here are my comments…

5. Prototype Implementation

 A prototype implementation is openly available.  The MIME
 instructions for retrieval are:

Malamud & Rose [Page 7] RFC 1528 Remote Printing – Technical Procedures October 1993

    MIME-Version: 1.0
    Content-Type: multipart/alternative;
            boundary="----- =_aaaaaaaaaa0"
    Content-Description:  pointers to ftp and e-mail access
  1. —— =_aaaaaaaaaa0

Content-Type: message/external-body;

            access-type="mail-server";
            server="archive-server@ftp.ics.uci.edu"
    Content-Type: application/octet-stream; type="tar";
            x-conversions="x-compress"
    Content-ID: <4599.735726126.1@dbc.mtview.ca.us>
    mimesend mrose/tpc/rp.tar.Z
  1. —— =_aaaaaaaaaa0

Content-Type: message/external-body;

            access-type="anon-ftp"; name="rp.tar.Z";
            directory="mrose/tpc"; site="ftp.ics.uci.edu"
    Content-Type: application/octet-stream; type="tar";
            x-conversions="x-compress"
    Content-ID: <4599.735726126.2@dbc.mtview.ca.us>
  1. —— =_aaaaaaaaaa0–
 This package contains software for UNIX-based systems, and was
 developed and tested under SunOS, with an openly-available facsimile
 package (Sam Leffler's FlexFAX package), and contains information for
 sites acting as either client or server participants, and zone
 administrators.

Malamud & Rose [Page 8] RFC 1528 Remote Printing – Technical Procedures October 1993

6. Future Issues

 Note that several issues are not addressed, e.g.,
    o determining which content-types and character sets are
      supported by a remote printer server;
    o introduction of authentication, integrity, privacy,
      authorization, and accounting services;
    o preferential selection of a remote printer server; and,
    o aggregation of multiple print recipients in a single
      message.
 Subsequent work might consider these issues in detail.

7. Security Considerations

 Internet mail may be subject to monitoring by third parties, and in
 particular, message relays.

8. Acknowledgements

 This document is based on RFC 1486, "An Experiment in Remote
 Printing".

9. References

 [1] Crocker, D., "Standard for the Format of ARPA Internet Text
     Messages", STD 11, RFC 822, UDEL, August 1982.
 [2] Partridge, C., "Mail Routing and the Domain System" STD 14, RFC
     974, CSNET CIC BBN, January 1986.
 [3] Mockapetris, P., "Domain Names -- Concepts and Facilities", STD
     13, RFC 1034, USC/Information Sciences Institute, November 1987).
 [4] Mockapetris, P., "Domain Names -- Implementation and
     Specification", STD 13, RFC 1035, USC/Information Sciences
     Institute, November 1987.
 [5] Borenstein, N., and N. Freed, "MIME (Multipurpose Internet Mail
     Extensions) Part One: Mechanisms for Specifying and Describing
     the Format of Internet Message Bodies", RFC 1521, Bellcore,
     Innosoft, September 1993.

Malamud & Rose [Page 9] RFC 1528 Remote Printing – Technical Procedures October 1993

10. Authors' Addresses

 Carl Malamud
 Internet Multicasting Service
 Suite 1155, The National Press Building
 Washington, DC 20045
 US
 Phone: +1 202 628 2044
 Fax:   +1 202 628 2042
 Email: carl@malamud.com
 Marshall T. Rose
 Dover Beach Consulting, Inc.
 420 Whisman Court
 Mountain View, CA  94043-2186
 US
 Phone: +1 415 968 1052
 Fax:   +1 415 968 2510
 Email: mrose@dbc.mtview.ca.us

Malamud & Rose [Page 10] RFC 1528 Remote Printing – Technical Procedures October 1993

Appendix A. The application/remote-printing Content-Type

 (1) MIME type name: application
 (2) MIME subtype name: remote-printing
 (3) Required parameters: none
 (4) Optional parameters: none
 (5) Encoding considerations: 7bit preferred
 (6) Security considerations: none
 (7) Specification:
 The "application/remote-printing" content-type contains originator
 and recipient information used when generating a cover-sheet.  Using
 the ABNF notation of RFC 822, the syntax for this content is:
 <content>         ::=  <recipient-info> CRLF
                        <originator-info>
                        [CRLF <cover-info>]
 <recipient-info>  ::=   "Recipient"    ":" <value> CRLF
                          <address-info>
 <originator-info> ::=   "Originator"   ":" <value> CRLF
                           <address-info>
 <address-info>    ::=  ["Title"        ":" <value> CRLF]
                        ["Department"   ":" <value> CRLF]
                        ["Organization" ":" <value> CRLF]
                        ["Mailstop"     ":" <value> CRLF]
                        ["Address"      ":" <value> CRLF]
                        ["Telephone"    ":" <value> CRLF]
                         "Facsimile"    ":" <value> CRLF
                        ["Email"        ":" <value> CRLF]
 <value>           ::=  *text
                        [CRLF LWSP-char     <value>     ]
 <cover-info>      ::=  *(*text CRLF)
 Note that the value of the "Email" field is an RFC 822 mailbox
 address.

Malamud & Rose [Page 11] RFC 1528 Remote Printing – Technical Procedures October 1993

Appendix B. The image/tiff Content-Type

 (1) MIME type name: image
 (2) MIME subtype name: tiff
 (3) Required parameters: none
 (4) Optional parameters: none
 (5) Encoding considerations: base64
 (6) Security considerations: none
 (7) Published specification: TIFF class F, as defined in:
 Tag Image File Format (TIFF)  revision 6.0
 Developer's Desk
 Aldus Corporation
 411 First Ave. South
 Suite 200
 Seattle, WA  98104
 206-622-5500

Malamud & Rose [Page 12]

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