Dynamic Host Configuration Working Group                     Steve Drach
INTERNET-DRAFT                                    Sun Microsystems, Inc.
                                                             August 1998
                                                   Expires February 1999

              DHCP Option for User Authentication Protocol

Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
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   This document defines a DHCP [1] option that contains a pointer to a
   User Authentication Protocol server that provides user authentication
   services for clients that conform to The Open Group Network Computer
   Technical Standard.


   The Open Group Network Computer Technical Standard, a product of The
   Open Group's Network Computer Working Group (NCWG), defines a network
   computer user authentication facility named the User Authentication
   Protocol (UAP).

   UAP provides two levels of authentication, basic and secure.  Basic
   authentication uses the Basic Authentication mechanism defined in the
   HTTP 1.1 [2] specification.  Secure authentication is simply basic
   authentication encapsulated in an SSLv3 [3] session.

   In both cases, a UAP client needs to obtain the IP address and port
   of the UAP service.  Additional path information may be required,

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   depending on the implementation of the service.  A URL [4] is an
   excellent mechanism for encapsulation of this information since many
   UAP servers will be implemented as components within legacy HTTP/SSL

   Most UAP clients have no local state and are configured when booted
   through DHCP.  No existing DHCP option [5] has a data field that
   contains a URL.  Option 72 contains a list of IP addresses for WWW
   servers, but it is not adequate since a port and/or path can not be
   specified.  Hence there is a need for an option that contains a URL.

User Authentication Protocol Option

   This option specifies a URL pointing to a user authentication service
   that will process authentication requests encapsulated in the User
   Authentication Protocol (UAP).  UAP servers can accept either HTTP
   1.1 or SSLv3 connections.  If the URL does not contain a port
   component, the normal default port is assumed (i.e., port 80 for http
   and port 443 for https).

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   |     Code      |    Length     |   URL

      Code    TBD

      Length  The length of the data field (i.e., URL) in bytes.

      URL     URL pointing to the UAP service.


   [1]  Droms, R., "Dynamic Host Configuration Protocol", RFC-2131,
        March 1997.

   [2]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H., and T.
        Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC-
        2068, January 1997.

   [3]  Freier, A., Karlton, P., and P. Kocher, "The SSL Protocol, Ver-
        sion 3.0", Internet Draft, November 1996.

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   [4]  Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
        Resource Locators (URL)", RFC-1738, December 1994.

   [5]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
        Extensions", RFC-2132, March 1997.

Security Considerations

   DHCP currently provides no authentication or security mechanisms.
   Potential exposures to attack are discussed in section 7 of the DHCP
   protocol specification.

Author's Address

   Steve Drach
   Sun Microsystems, Inc.
   901 San Antonio Road
   Palo Alto, CA 94303

   Phone: (650) 960-1300

   EMail: drach@sun.com

Drach                                                           [Page 3]