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123 lines
3.6 KiB
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123 lines
3.6 KiB
Plaintext
Date: 30 Nov 1983 0310 PST
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From: Eric P. Scott <EPS at JPL-VAX>
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Reply-To: EPS at JPL-VAX
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To: TCP-IP at SRI-NIC
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Re: Not an RFC inspired by a somewhat infamous computer game
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Network Hacking Group E. P. Scott
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Request for Kludges: XXX JPL
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November, 1983
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Updates: RFC 821
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SMTP POLYMORPH COMMAND
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Preface
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The purpose of this document is to present a partial workaround for
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an anticipated future problem in the ARPA Internet. It is hoped that
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it will prove unnecessary to adopt such an overtly ridiculous
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strategy as a practical means of preserving connectivity. The views
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expressed are the author's own and do not necessarily reflect those
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of NASA, the Jet Propulsion Laboratory, or the California Institute
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of Technology. Treat them as satirical in nature.
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Introduction
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Current plans call for the activation of "access control filters" in
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the six IP gateways that bridge MILNET and ARPANET on February 1,
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1984 [1]. In most cases communications will be restricted to mail
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only. Sites such as ours which are in the wrong Community Of
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Interest vis a vis the sites they need to communicate with because
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the politics run counter to legitimate research needs will be unable
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to participate as functional nodes after this date. A trivial
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solution is of course to abandon the plan to segregate the two
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networks [2]. Assuming that this does not happen and the controls go
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into effect on schedule, it will be necessary to defeat the
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"protection" offered in order to "stay in business" (unless the
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Powers That Be can be convinced to put us back on the other side of
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the fence before then). Even so, other sites share a similar plight.
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Description
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I propose to implement an extension to the SMTP protocol [3] that
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would allow services such as Telnet [4] to be accessed via port 25.
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The extension consists of the new command POLY which accepts as its
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parameter a keyword identifying the service desired. Successful
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execution of POLY returns a 250 reply and replaces the SMTP server.
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It is assumed that POLY would be given as the first command in a
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session in order to avoid considering the implications of arbitrary
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placement. A typical scenario might look like:
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@TELNET
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TELNET>INTERNET (HOST) JPL-VLSI (ON PORT) 25
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Trying... Open
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220 JPL-VLSI.DDN SMTP Service
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POLY TELNET
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250 Toto, I don't think we're in SMTP anymore!
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JPL VLSI Design Center VAX...
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Scott [Page 1]
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SMTP Polymorph Command RFK XXX
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Syntax
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POLY <SP> <string> <CRLF>
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Replies
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S: 250
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E: 500, 501, 502, 503, 504, 421
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Concluding Comments
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"Polymorph" commands are nothing new; SMTP's TURN can be considered
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one; perhaps a better example is the Telnet SUPDUP Option [5].
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FTP presents a special problem since data is not transmitted over
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the telnet connection.
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This won't help (most) TAC users.
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References
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[1] DDN Program Management Office, "Further Details on the MILNET/
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ARPANET Split," in DDN Newsletter no. 28, Network Information
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Center, SRI International, July 1983.
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[2] Muuss, M., "On the Undesirability of `Mail Bridges' as a
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Security Measure," in TCP-IP Digest, vol. 2, no. 18, BRL,
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October 1983.
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[3] Postel, J., "Simple Mail Transfer Protocol," RFC 821, USC/
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Information Sciences Institute, August 1982.
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[4] Postel, J. and J. Reynolds, "Telnet Protocol Specification,"
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RFC 854, USC/Information Sciences Institute, May 1983.
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[5] Crispin, M., "Telnet SUPDUP Option," RFC 736, NIC 42213,
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Stanford Artificial Intelligence Laboratory, October 1977.
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Scott [Page 2]
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