idnits 2.17.00 (12 Aug 2021) /tmp/idnits52787/draft-aboba-dhc-mdns-conf-01.txt: ** The Abstract section seems to be numbered Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** Looks like you're using RFC 2026 boilerplate. This must be updated to follow RFC 3978/3979, as updated by RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- ** The document seems to lack a 1id_guidelines paragraph about Internet-Drafts being working documents -- however, there's a paragraph with a matching beginning. Boilerplate error? Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == Line 46 has weird spacing: '...pose of this ...' == Line 121 has weird spacing: '...host will be ...' == Line 225 has weird spacing: '...imed to perta...' == Line 269 has weird spacing: '...>, and expir...' == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords -- however, there's a paragraph with a matching beginning. Boilerplate error? (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (10 March 2000) is 8100 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-01) exists of draft-aboba-dnsext-mdns-00 -- Possible downref: Normative reference to a draft: ref. '3' Summary: 4 errors (**), 0 flaws (~~), 7 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Levon Esibov 3 INTERNET-DRAFT Bernard Aboba 4 Category: Standards Track Dave Thaler 5 Microsoft 6 10 March 2000 7 Expires: October 1, 2000 9 Multicast DNS Configuration Option 11 This document is an Internet-Draft and is in full conformance with all 12 provisions of Section 10 of RFC2026. 14 Internet-Drafts are working documents of the Internet Engineering Task 15 Force (IETF), its areas, and its working groups. Note that other groups 16 may also distribute working documents as Internet- Drafts. 18 Internet-Drafts are draft documents valid for a maximum of six months 19 and may be updated, replaced, or obsoleted by other documents at any 20 time. It is inappropriate to use Internet-Drafts as reference material 21 or to cite them other than as "work in progress." 23 The list of current Internet-Drafts can be accessed at 24 http://www.ietf.org/ietf/1id-abstracts.txt 26 The list of Internet-Draft Shadow Directories can be accessed at 27 http://www.ietf.org/shadow.html. 29 1. Copyright Notice 31 Copyright (C) The Internet Society (2000). All Rights Reserved. 33 2. Abstract 35 This document defines a new DHCP option which is passed from the DHCP 36 Server to the DHCP Client to specify the multicast DNS configuration. 38 3. Introduction 40 Multicast DNS was first defined in [5], and behavior was further 41 specified in [3]. The Dynamic Host Configuration Protocol (DHCP)[1] 42 provides a framework for passing configuration information to hosts on a 43 TCP/IP network. RFC 2132 [2] allows DHCP servers to specify 44 configuration information for various kinds of name servers to be passed 45 to DHCP clients. However, no information is provided as to the 46 configuration desired for multicast DNS. The purpose of this document 47 is to allow DHCP servers to specify the multicast DNS configuration to 48 be used by DHCP clients. 50 3.1. Requirements terminology 52 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 53 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this 54 document are to be interpreted as described in RFC 2119 [4]. 56 3.2. DHCP terminology 58 This document uses the following terms: 60 DHCP client 61 DHCP client or "client" is an Internet host using DHCP to 62 obtain configuration parameters such as a network address. 64 DHCP server 65 A DHCP server or "server" is an Internet host that returns 66 configuration parameters to DHCP clients. 68 4. Format of the multicast DNS configuration option 70 The following diagram defines the format of the multicast DNS 71 configuration option: 73 0 1 2 74 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 75 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 76 | Code | Length | Node Type | 77 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 79 Code 81 TBD 83 Length 85 1 87 Node type 89 The node type field, which is one octet, describes how the host 90 behaves as multicast DNS querier and listener. Values are defined as 91 follows: 93 Value Node Type 94 ----- --------- 95 0x1 B-node 96 0x2 P-node 97 0x3 Reserved 98 0x4 M-node 99 0x5 - 0x7 Reserved 100 0x8 H-node 101 0x9 - 0xFF Reserved 103 4.1. B-node 105 B-nodes MUST act as multicast DNS queriers and listeners, but MUST NOT 106 send unicast DNS queries. As a result, they are unable to resolve names 107 outside the scope of the multicast DNS, as defined in [3]. 109 Hosts configured as B-nodes MUST listen for mDNS queries on both the 110 linklocal and local scope addresses, and MUST respond to mDNS queries as 111 described in [3]. 113 4.2. P-node 115 P-nodes MUST only send unicast DNS queries, and MUST NOT listen for 116 multicast DNS queries or respond to them in any way. Hosts configured as 117 P-nodes MUST NOT send multicast DNS queries for any purpose, including 118 DNS server location. By default, both IPv4 and IPv6 hosts that are 119 configured via DHCP but do not receive a multicast DNS configuration 120 option behave as P-nodes. If no DNS server option is provided, a P-node 121 host will be unable to resolve names. 123 4.3. M-node 125 M-nodes MUST use multicast DNS queries for resolving names prior to 126 querying the DNS server using unicast. M-nodes configured without a DNS 127 server will send only multicast DNS queries, and will be unable to 128 resolve names outside the scope of the multicast DNS, as defined in [3]. 130 Hosts configured as M-nodes MUST listen for mDNS queries on both the 131 linklocal and local scope addresses, and MUST respond to mDNS queries as 132 described in [3]. 134 4.4. H-nodes 136 H-nodes MUST send multicast DNS queries only if they have not been able 137 to resolve the name via a query to a DNS server using unicast. H-nodes 138 lacking a DNS server will send only multicast DNS queries, and will be 139 unable to resolve names outside the scope of the multicast DNS as 140 defined in [3]. 142 Hosts configured as H-nodes MUST listen for mDNS queries on both the 143 linklocal and local scope addresses, and MUST respond to mDNS queries as 144 described in [3]. H-nodes MUST NOT send mDNS queries without first 145 querying the unicast DNS server if one is available. 147 5. Scalability considerations 149 Since B and M-nodes function as multicast DNS listeners as well as 150 multicast DNS queriers of first resort, the presence of these nodes can 151 result in considerable multicast traffic propagating within the local 152 administrative scope zone. This could represent a scalability problem in 153 large enterprise networks, and so in this scenario, configuration of 154 hosts as B and M-nodes is discouraged. Instead, it is recommended that 155 enterprise networks deploy dynamic DNS utilizing hosts configured as P- 156 nodes, which is the default behavior where no mDNS configuration option 157 is provided. 159 6. References 161 [1] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 162 1997. 164 [2] Alexander, S., Droms, R., "DHCP Options and BOOTP Vendor 165 Extensions", RFC 2132, March 1997. 167 [3] Esibov, L., Aboba, B., Thaler, D. "Multicast DNS", Internet draft 168 (work in progress), draft-aboba-dnsext-mdns-00.txt, March 2000. 170 [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement 171 Levels", BCP 14, RFC 2119, March 1997. 173 [5] Braden, R., "Requirements for Internet Hosts -- Application and 174 Support", RFC 1123, October 1989. 176 7. Security Considerations 178 The option described in this draft may be used in situations where DHCP 179 is authenticated or unauthenticated. In situations where authenticated 180 DHCP is not used, it is possible for a rogue DHCP server to respond to 181 the DHCP client with an inappropriate mDNS configuration option. For 182 example, the rogue DHCP server could specify an mDNS configuration 183 option of 0x1. This would cause the host to become both an mDNS querier 184 and listener (B-node). Were hosts to be widely configured this way, this 185 could result in propagation of mDNS queries throughout the enterprise. 187 8. IANA Considerations 189 This draft does not create any new number or name spaces for IANA 190 administration. 192 9. Acknowledgements 194 This draft has been enriched by comments from Erik Guttman of Sun 195 Microsystems. 197 10. Authors' Addresses 199 Levon Esibov 200 Microsoft Corporation 201 One Microsoft Way 202 Redmond, WA 98052 204 EMail: levone@microsoft.com 206 Bernard Aboba 207 Microsoft Corporation 208 One Microsoft Way 209 Redmond, WA 98052 211 Phone: +1 (425) 936-6605 212 EMail: bernarda@microsoft.com 214 Dave Thaler 215 Microsoft Corporation 216 One Microsoft Way 217 Redmond, WA 98052 219 Phone: +1 (425) 703-8835 220 EMail: dthaler@microsoft.com 222 11. Intellectual Property Statement 224 The IETF takes no position regarding the validity or scope of any 225 intellectual property or other rights that might be claimed to pertain 226 to the implementation or use of the technology described in this 227 document or the extent to which any license under such rights might or 228 might not be available; neither does it represent that it has made any 229 effort to identify any such rights. Information on the IETF's 230 procedures with respect to rights in standards-track and standards- 231 related documentation can be found in BCP-11. Copies of claims of 232 rights made available for publication and any assurances of licenses to 233 be made available, or the result of an attempt made to obtain a general 234 license or permission for the use of such proprietary rights by 235 implementors or users of this specification can be obtained from the 236 IETF Secretariat. 238 The IETF invites any interested party to bring to its attention any 239 copyrights, patents or patent applications, or other proprietary rights 240 which may cover technology that may be required to practice this 241 standard. Please address the information to the IETF Executive 242 Director. 244 12. Full Copyright Statement 246 Copyright (C) The Internet Society (2000). All Rights Reserved. 247 This document and translations of it may be copied and furnished to 248 others, and derivative works that comment on or otherwise explain it or 249 assist in its implmentation may be prepared, copied, published and 250 distributed, in whole or in part, without restriction of any kind, 251 provided that the above copyright notice and this paragraph are included 252 on all such copies and derivative works. However, this document itself 253 may not be modified in any way, such as by removing the copyright notice 254 or references to the Internet Society or other Internet organizations, 255 except as needed for the purpose of developing Internet standards in 256 which case the procedures for copyrights defined in the Internet 257 Standards process must be followed, or as required to translate it into 258 languages other than English. The limited permissions granted above are 259 perpetual and will not be revoked by the Internet Society or its 260 successors or assigns. This document and the information contained 261 herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE 262 INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR 263 IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 264 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 265 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." 267 13. Expiration Date 269 This memo is filed as , and expires 270 October 1, 2000.