Network Working Group S. Drach
Request for Comments: 2485 Sun Microsystems
Category: Standards Track January 1999
DHCP Option for The Open Group's User Authentication Protocol
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document defines a DHCP  option that contains a list of
pointers to User Authentication Protocol servers that provide user
authentication services for clients that conform to The Open Group
Network Computing Client Technical Standard .
The Open Group Network Computing Client Technical Standard, a product
of The Open Group's Network Computing Working Group (NCWG), defines a
network computing client 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  specification. Secure authentication is simply basic
authentication encapsulated in an SSLv3  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,
depending on the implementation of the service. A URL  is an
excellent mechanism for encapsulation of this information since many
UAP servers will be implemented as components within legacy HTTP/SSL
Drach Standards Track [Page 1]RFC 2485 DCHP Option for the Open Group's UAP January 1999
Most UAP clients have no local state and are configured when booted
through DHCP. No existing DHCP option  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 list
User Authentication Protocol Option
This option specifies a list of URLs, each pointing to a user
authentication service that is capable of processing authentication
requests encapsulated in the User Authentication Protocol (UAP). UAP
servers can accept either HTTP 1.1 or SSLv3 connections. If the list
includes a URL that does not contain a port component, the normal
default port is assumed (i.e., port 80 for http and port 443 for
https). If the list includes a URL that does not contain a path
component, the path /uap is assumed.
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 list
Length The length of the data field (i.e., URL list) in
URL list A list of one or more URLs separated by the ASCII
space character (0x20).
 Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
 Technical Standard: Network Computing Client, The Open Group,
Document Number C801, October 1998.
 Fielding, R., Gettys, J., Mogul, J., Frystyk, H., and T.
Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC
2068, January 1997.
 Freier, A., Karlton, P., and P. Kocher, "The SSL Protocol,
Version 3.0", Netscape Communications Corp., November 1996.
Standards Information Base, The Open Group,
Drach Standards Track [Page 2]RFC 2485 DCHP Option for the Open Group's UAP January 1999
 Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
Resource Locators (URL)", RFC 1738, December 1994.
 Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
DHCP currently provides no authentication or security mechanisms.
Potential exposures to attack are discussed in section 7 of the DHCP