One document matched: draft-eastlake-ip-mime-06.txt
Differences from draft-eastlake-ip-mime-05.txt
INTERNET-DRAFT D. Eastlake 3rd
Expires: July 2002 January 2002
IP over MIME
-- ---- ----
<draft-eastlake-ip-mime-06.txt>
Status of This Document
Distribution of this document is unlimited. Comments should be sent
to the author.
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026. Internet-Drafts are
working documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
The MIME encoding of IP packets is standardized so they can
conveniently be sent via MAIL, HTTP, etc. This may be convenient for
transmitting packets for analysis or for creating application level
tunnels.
Acknowledgement
Helpful suggestions from Matt Crawford, Mike Ditto, and Stanislav
Shalunov have been incorporated herein.
D. Eastlake 3rd [Page 1]
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Table of Contents
Status of This Document....................................1
Abstract...................................................1
Acknowledgement............................................1
Table of Contents..........................................2
1. Introduction............................................3
2. MIME Type Specification.................................4
3. Security Considerations.................................6
References.................................................7
Author's Address...........................................7
Expiration and File Name...................................8
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1. Introduction
The Internet Protocol (IP [RFC 791]) has been profiled for
transmission over a wide variety of media including Ethernet [RFC
894], point to point circuits [RFC 1661], FDDI [RFC 1390], and even
avian carriers [RFC 1149], etc. And one of the most popular encoding
and labeling (AKA, tagging and bagging) techniques defined for the
TCP/IP protocol suite is the MIME encoding [RFC 2045, 2046] used, for
example, in email, the web, and net news. This document rectifies the
omission that IP over MIME has not previously been specified.
An unambiguous MIME encoding for IP datagrams is useful in their
transmission for monitoring, analysis, debugging, or illustrative
purposes.
In addition, IP over MIME can be effective as one component in
creating application level tunnels including those that bypass
firewall protections [RFC 3093]. With the aid of cooperative
software running within a firewall, unrestricted, if slow, IP
connectivity can be established. The following diagram shows such a
possible tunnel configuration:
Internet/Firwalls
SMTP/HTTP/... |
+-------------|------------+
| | |
Host A |h/w | h/w| Host B
+------------|----------+ | +---------|-------------+
| | | | | | |
| v | | | v |
| +-----------------+ | | | +-----------------+ |
| | Real IP | Stack | | | | Real | IP Stack | |
| +-----------------+ | | +-----------------+ |
| ^s/w ^ | | ^ s/w^ |
| : | | | | : |
| : v | | v : |
| : +------------+ | | +------------+ : |
| :.>| Application| | | |Application |<.: |
| +------------+ | | +------------+ |
+-----------------------+ +-----------------------+
Hosts A and B have hardware network interface (h/w) by which they can
communicate using IP. Applications capable of MIME encoding IP exist
on both Hosts. Through proper registry by the applications with
their local IP stack (which may require special privileges), real IP
stack to real IP stack IP connectivity can be established. Depending
on the addressing environments of Host A and B, incorporation of NAT
[RFC 3022] technology into these applications may also be helpful.
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2. MIME Type Specification
MIME media type name: APPLICATION
MIME subtype name: IP
Required parameters: version
version=n
This parameter exposes the IP Version number [RFC 791] in the
MIME Content-Type.
Optional parameters: dilation, address
dilation=nnn
Typically IP packets will be MIME labeled for transmission over
email or other application level protocols. Such transmission
is normally slower than lower level network protocols. While
this is not much of a concern if a packet is just being
communicated for analysis, if such transmission is used to
establish connectivity, the sender of a datagram may wish to
advise the recipient of the estimated time dilation factor.
For example, if datagrams typically take around a second and
occasionally up to ten seconds end-to-end but it is more like a
minute and occasionally up to ten minutes if they are MIME
encoded in email, a "dilation=60" parameter would be
reasonable.
Note: Although IP and TCP are defined as timing independent
protocols, many implementations actually have timeouts built
in. In some cases, an effective technique to defeat these
timeouts is to repeatedly resend the last packet received.
This is, if a MIME encoded TCP packet is being sent from Host A
to Host B in the figure above where the applications are
gatewaying the packets to the real IP stack, repeated
transmission of this packet by the application on Host B to the
stack may stave off timeouts. Similarly, the repeated
transmission to the real IP stack on Host A of the last reply
TCP packet may stave off timeouts there.
address=xxx
Full, if slow, IP connectivity via an application level
protocol such as SMTP [RFC 2821, 2822] might require that
routing, tunneling, and/or interface entries be installed at
each end. Routing entries would be best created or updated by
routing protocol messages and the establishment of tunnels is
beyond the scope of this MIME type. However, the address=
parameter enables the sender to optionally indicate an IP
address for itself. This may only be useful in cases where the
sender knows an address that is available for itself in the
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recipient's addressing environment. It can be viewed as a
replacement for ARP [RFC 826] on the possible path to the
source of the APPLICATION/IP object via the same application
level protocol. (A receiver of such an APPLICATION/IP object
with an address= parameter might reasonably require that it be
authenticated as meeting their policy as to from whom they
would accept such information. For example, they could ignore
address= parameters unless the APPLICATION/IP object was
wrapped in an acceptable MULTIPART/SIGNED [RFC 1847]
authentication, although that implies some trust relationship
between the parties.)
Examples:
address="10.100.1.10"
address="1080:0:0:0:8:800:200C:4171"
Encoding considerations: Because of the binary nature of the body,
BASE64 transfer encoding should normally be used.
Security considerations: Care should be taken under any circumstance
where APPLCIATION/IP content can be treated as a "live" packet.
MULTIPART/ENCRYPTED and MULTIPART/SIGNED [RFC 1847] may be used
to further disguise and/or authenticate MIME packaged IP
traffic.
Interoperability considerations: See [draft-eastlake-ip-mime-*.txt].
MULTIPART/MIXED [RFC 2046] may be used to package multiple IP
datagrams together.
Published specification: See [draft-eastlake-ip-mime-*.txt].
Applications which use this media type: Not yet in use. See also
[RFC 3093].
Additional information: (none)
Person & email address to contact for further information:
Donald E. Eastlake 3rd, dee3@torque.pothole.com
Intended usage: LIMITED USE
Author/Change controller: IETF
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3. Security Considerations
See security considerations in Section 2 above.
The APPLICATION/IP MIME type is particularly suitable as an
illustration of the weakness of the "crunchy outside, soft interior"
security model which places undue dependence on firewalls or similar
perimeter security. It would require a possibly privileged
accomplice or some other weakness to install code within a security
perimeter that would actually process incoming APPLICATION/IP data;
however, once this is done, general, if slow, IP connectivity can
normally be established because HTTP, email, and the like are
typically given free passage through firewalls.
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References
RFC 791 - "Internet Protocol", J. Postel, Sep-01-1981.
RFC 826 - Ethernet Address Resolution Protocol, D.C. Plummer, Nov-
01-1982.
RFC 894 - "Standard for the transmission of IP datagrams over
Ethernet networks", C. Hornig, Apr-01-1984.
RFC 1149 - "Standard for the transmission of IP datagrams on avian
carriers", D. Waitzman, Apr-01-1990.
RFC 1390 - "Transmission of IP and ARP over FDDI Networks", D. Katz,
January 1993.
RFC 1661 - "The Point-to-Point Protocol (PPP)", W. Simpson, July
1994.
RFC 1847 - "Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", J. Galvin, S. Murphy, S. Crocker, N. Freed,
October 1995.
RFC 2045 - "Multipurpose Internet Mail Extensions (MIME) Part One:
Format of Internet Message Bodies", N. Freed & N. Borenstein,
November 1996.
RFC 2046 - "Multipurpose Internet Mail Extensions (MIME) Part Two:
Media Types", N. Freed, N. Borenstein, November 1996.
RFC 2821 - "Simple Mail Transfer Protocol", J. Klensin, April 2001.
RFC 2822 - "Internet Message Format", P. Resnick, April 2001.
RFC 3022 - "Traditional IP Network Address Translator (Traditional
NAT)", P. Srisuresh, K. Egevang, January 2001.
RFC 3093 - "Firewall Enhancement Protocol (FEP)", M. Gaynor, S.
Bradner, 1 April 2001.
Author's Address
Donald E. Eastlake, 3rd
155 Beaver Street
Milford, MA 01757 USA
Telephone: +1 508-634-2066 (h)
+1 508-851-8280 (w)
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fax: +1 508-851-8507 (w)
email: dee3@torque.pothole.com
Expiration and File Name
This draft expires July 2002.
Its file name is draft-eastlake-ip-mime-06.txt.
D. Eastlake 3rd [Page 8]
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