Internet Engineering Task Force J. Luciani INTERNET DRAFT Novell, Inc. 10 February 1998 DHCP Options for Novell IPX Compatibility draft-ietf-dhc-ipxcmd-00.txt Status of This Memo This document is a submission to the Dynamic Host Configuration Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the dhcp-v4@bucknell.edu mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft. 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (North Europe), ftp.nis.garr.it (South Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This document defines a new DHCP option for delivering configuration information to hosts utilizing the IPX Compatibility feature of Novell's NetWare. The option carries several operational parameters that allow network administrators to customize their installations. Luciani Expires ????? [Page 1] Internet Draft DHCP Option for IPX Compatibility 10 February 1998 1. Introduction The IPX Compatibility feature of Novell's NetWare systems is a tool that can be used by network administrators to migrate their IPX based networks to IP based networks. The IPX Compatibility feature provides the connectivity necessary for IPX Client/Server applications to communicate between nodes that connect to the IP Internet (IP Nodes). The IPX Compatibility feature also allows IPX Client/Server applications to communicate between IP Nodes and nodes that connect to IPX networks (IPX Nodes). Connectivity between IPX Nodes and IP Nodes is achieved through the use of gateways called Migration Agents. This specification describes a DHCP option [1] that can carry one or several IPX Compatibility configuration parameters. Each configuration parameter is treated as a separate sub-option by the hosts. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. [2] 2. IPX Compatibility Option This option specifies one or more sub-options carrying IPX Compatibility information. The sub-options that can be carried by this option are described in the sections that follow. The code for this option is ??, and its maximum length is 255 octets. Code Len Sub-Option 1 Sub-Option 2 +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-- | ?? | n | a1 | a2 | a3 | a4 | a1 | a2 | a3 | a4 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-- The 'Len' field specifies the number of octets containing sub-option information within the DHCP option. Each sub-option will contain a code followed by a length that specifies the number of octets containing configuration parameter information within the sub-option. Sub Sub Code Len Configuration Parameter(s) +-----+-----+-----+-----+-----+-----+-----+-----+-- | x | n | a1 | a2 | a3 | a4 | a6 | a7 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-- Luciani Expires ????? [Page 2] Internet Draft DHCP Option for IPX Compatibility 10 February 1998 2.1 IPX Compatibility Virtual Network Number Sub-Option This sub-option specifies the network number of the virtual IPX network created by the IPX Compatibility feature. The code for this sub-option is 1. The length specified in the 'Len' field of this sub-option MUST always be 4 octets. Code Len IPX Network Number +-----+-----+-----+-----+-----+-----+ | 1 | 4 | a1 | a2 | a3 | a4 | +-----+-----+-----+-----+-----+-----+ 2.2 IPX Compatibility Stale Time Sub-Option This sub-option specifies the minimum interval in minutes that must expire before hosts try to refresh their Migration Agent addressing information. This sub-option is ignored by hosts when the Migration Agent sub-option is carried along with this DHCP option. A Stale Time of zero indicates that hosts should not refresh their Migration Agent addressing information. The code for this sub-option is 2. The length specified in the 'Len' field of this sub-option MUST always be 2 octets. Code Len Stale Time +-----+-----+-----+-----+ | 2 | 2 | a1 | a2 | +-----+-----+-----+-----+ 2.3 Migration Agents Sub-Option This option specifies the addresses of one or more Migration Agent servers for the IP Nodes to use for communicating with IPX Nodes. The code for this sub-option is 3. The minimum length specified in the 'Len' field is 4 octets, and this length MUST be a multiple of 4. Code Len Address 1 Address 2 +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-- | 3 | n | a1 | a2 | a3 | a4 | a1 | a2 | a3 | a4 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-- Luciani Expires ????? [Page 3] Internet Draft DHCP Option for IPX Compatibility 10 February 1998 3. Examples The sections that follow illustrate the encoding of different sets of information within the IPX Compatibility option. 3.1 Option ?? Carrying Virtual Network Number and Stale Time Information The option ?? encoding shown below specifies the value 0x00ABCDEF as the IPX Compatibility Virtual Network Number parameter and the value 0x0014 (20 minutes) as the IPX Compatibility Stale Time parameter. Code Len +-----+-----+ | ?? | 0A | +-----+-----+ IPX Compatibility Virtual Network Number Sub-Option +-----+-----+-----+-----+-----+-----+ | 01 | 04 | 00 | AB | CD | EF | +-----+-----+-----+-----+-----+-----+ IPX Compatibility Stale Time Sub-Option +-----+-----+-----+-----+ | 02 | 02 | 00 | 14 | +-----+-----+-----+-----+ 3.2 Option ?? Carrying Migration Agent Addressing Information The option ?? encoding shown below specifies the addresses 137.65.147.87 (0x89419357) and 137.65.147.68 (0x89419344) as the addreses of Migration Agent servers. Code Len +-----+-----+ | ?? | 0A | +-----+-----+ Migration Agents Sub-Option +-----+-----+-----+-----+-----+-----+ | 03 | 08 | 89 | 41 | 93 | 57 | +-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+ | 89 | 41 | 93 | 44 | +-----+-----+-----+-----+ Luciani Expires ????? [Page 4] Internet Draft DHCP Option for IPX Compatibility 10 February 1998 4. References [1] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC-2132, March 1997. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC-2119, March 1997. [3] Droms, R., "Dynamic Host Configuration Protocol", RFC-2131, March 1997. 5. Security Considerations DHCP currently provides no authentication or security mechanisms. Potential exposures to attack are discussed in section 7 of the DHCP protocol specification [3]. In particular, these DHCP options allow an unauthorized DHCP server to misdirect an IPX Compatibility Node to a nonexistent Migration Agent server or to utilize an invalid IPX Virtual Network Number. 6. Author's Address Juan Carlos Luciani Novell, Inc. 122 E. 1700 S. Provo, Utah, 84606 Phone: +1 801 222 6000 EMail: jluciani@Novell.Com Luciani Expires ????? [Page 5] --=_2471FC62.60013DB2--