Service Location Working Group Jonathan Wood INTERNET DRAFT Sun Microsystems, Inc 9 August 1999 The wpad Abstract Service Type draft-ietf-svrloc-wpad-template-00.txt Status of This Memo This document is a submission by the Service Location Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the srvloc@srvloc.org mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 This document describes the wpad abstract type. The wpad service provides access to web proxy auto-discovery (WPAD) configuration files (CFILEs). This service type can be used in conjunction with the Service Location Protocol (SLP) to dynamically retrieve CFILEs which can automatically configure web browsers with suitable web proxies. 1. Introduction The Service Location Protocol is defined in [1]. Service templates Wood, Tam expires February 2000 [Page 1] INTERNET DRAFT August 1999 and abstract types are defined in [2]. The wpad abstract type is intended to organize information pertaining to the location and access method needed to dynamically obtain CFILEs. For more information on CFILEs and WPAD, see [3]. The content of the WPAD file is opaque as far as this service type is concerned. Different browsers may interpret CFILEs in different ways. Hence customized CFILEs may be needed to service various browsers. A "config-method" attribute is specified in the template to allow web browsers to use SLP to search for a suitable CFILE. CFILEs tell web browsers which web proxies are available, and how to select the proper one for its needs. This service type does NOT contain any information about how to directly access web proxies. Similarly, CFILEs do NOT contain any configuration information for other web browser functions. The wpad service is not an application configuration service. The concrete type should be the access protocol used to retrieve the CFILE. The URL should also specify the host that provides access to the CFILE, and a path relative to the server host that names the location of the CFILE. An example of a valid wpad service: URL follows: service:wpad:http://wserver.sun.com:8080/proxy-config/eng.proxy A configuration URL (CURL) as defined in [3] can be extracted from this service: URL simply by removing the leading "service:". 2. The "wpad" Abstract Service Name of submitter: "Jonathan Wood" Language of service template: en Security Considerations: If a web browser is tricked into retrieving a malicious CFILE, it could suffer denial-of-service attacks, or potentially betray confidential information. As such, the web browser should take care to ensure that the CFILE is not malicious. The use of SLP's protected scopes is a means of ensuring a CFILE's validity. Template text: -------------------------template begins here----------------------- template-type=wpad Wood, Tam expires February 2000 [Page 2] INTERNET DRAFT August 1999 template-version=0.0 template-description= This is an abstract service type for WPAD configuration URLs. template-url-syntax= url-path= ; an URL for the configuration data, as defined in [4]. config-method= string M X # The method of determining the configuration. # Since this may vary from browser to browser, clients should # include this attribute in search requests to ensure that they # get a configuration method that will be applicable to their # specific browser. # # The values must refer to a browser type. If two different browsers # use the same configuration method, they may use the same value for # this attribute. For example, if Wiz Software creates a new browser # that uses the same method as Netscape's Communicator (i.e. # Javascript), it may use the "communicator" value. communicator,ie,mosaic,hotjava access-protocol= string # The protocol to be used to access this CFILE. This attribute # is useful for UAs which wish to query for a set of preferred # access protocols. This attribute should match the access protocol # given in the concrete type. --------------------------template ends here------------------------ References: [1] E. Guttman, C. Perkins, J. Veizades, M. Day, "Service Location Protocol Version 2", RFC 2608, June 1999. [2] E. Guttman, C. Perkins, J. Kempf, "Service Templates and service: Schemes", RFC 2609, June 1999. [3] P. Gauthier, J. Cohen, M. Dunsmuir, C. Perkins, "Web Proxy Auto-Discovery Protocol", Internet Draft, July 1999 (Work In Progress) [4] T. Berners-Lee, R. Fielding, and L. Masinter. Uniform Resource Locators (URL): Generic Syntax and Semantics. RFC1738 as amended by RFC1808 Wood, Tam expires February 2000 [Page 3]