idnits 2.17.1 draft-senie-directed-broadcast-03.txt: 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: ---------------------------------------------------------------------------- ** Missing expiration date. The document expiration date should appear on the first and last page. ** Expected the document's filename to be given on the first page, but didn't find any == The page length should not exceed 58 lines per page, but there was 2 longer pages, the longest (page 2) being 60 lines == It seems as if not all pages are separated by form feeds - found 0 form feeds but 3 pages Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an Abstract section. ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. == The 'Updates: ' line in the draft header should list only the _numbers_ of the RFCs which will be updated by this document (if approved); it should not include the word 'RFC' in the list. -- The draft header indicates that this document updates RFC1812, but the abstract doesn't seem to mention this, which it should. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == Line 70 has weird spacing: '... use of dynam...' == Couldn't figure out when the document was first submitted -- there may comments or warnings related to the use of a disclaimer for pre-RFC5378 work that could not be issued because of this. Please check the Legal Provisions document at https://trustee.ietf.org/license-info to determine if you need the pre-RFC5378 disclaimer. -- The document date (March 1999) is 9175 days in the past. Is this intentional? Checking references for intended status: Best Current Practice ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2267 (ref. '2') (Obsoleted by RFC 2827) -- Possible downref: Non-RFC (?) normative reference: ref. '3' ** Obsolete normative reference: RFC 2002 (ref. '4') (Obsoleted by RFC 3220) -- Possible downref: Non-RFC (?) normative reference: ref. '5' Summary: 8 errors (**), 0 flaws (~~), 6 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 INTERNET-DRAFT D. Senie 3 Category: BCP Amaranth Networks Inc. 4 Updates: RFC 1812 March 1999 5 Expires in six months 7 Changing the Default for Directed Broadcasts in Routers 9 Status of this Memo 11 This document is an Internet-Draft and is in full conformance with 12 all provisions of Section 10 of RFC2026. 14 Internet-Drafts are working documents of the Internet Engineering 15 Task Force (IETF), its areas, and its working groups. Note that other 16 groups 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 21 material 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 Copyright Notice 31 Copyright (C) The Internet Society (1999). All Rights Reserved. 33 1. Introduction 35 Router Requirements [1] specifies that routers must receive and 36 forward directed broadcasts. It also specifies that routers MUST have 37 an option to disable this feature, and that this option MUST default 38 to permit the receiving and forwarding of directed broadcasts. While 39 directed broadcasts have uses, their use on the Internet backbone 40 appears to be comprised entirely of malicious attacks on other 41 networks. 43 Changing the required default for routers would help ensure new 44 routers connected to the Internet do not add to the problems already 45 present. 47 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 48 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 49 document are to be interpreted as described in RFC 2119. 51 2. Discussion 52 Damaging denial of service attacks led to the writing of [2] on 53 Ingress Filtering. Many network providers and corporate networks have 54 endorsed the use of these methods to ensure their networks are not 55 the source of such attacks. 57 A recent trend in Smurf Attacks [3] is to target networks which 58 permit directed broadcasts from outside their networks. By permitting 59 directed broadcasts, these systems become "Smurf Amplifiers." 61 While the continued implementation of ingress filters remains the 62 best way to limit these attacks, restricting directed broadcasts 63 should also receive priority. 65 Network service providers and corporate network operators are urged 66 to ensure their networks are not susceptible to directed broadcast 67 packets originating outside their networks. 69 Mobile IP [4] had provisions for using directed broadcasts in a 70 mobile node's use of dynamic agent discovery. While some 71 implementations support this feature, it is unclear whether it is 72 useful. Other methods of achieving the same result are documented in 73 [5]. It may be worthwhile to consider removing the language on using 74 directed broadcasts as Mobile IP progresses on the standards track. 76 3. Recommendation 78 Router Requirements [1] is updated as follows: 80 Section 4.2.2.11 (d) is replaced with: 82 (d) { , -1 } 84 Directed Broadcast - a broadcast directed to the specified network 85 prefix. It MUST NOT be used as a source address. A router MAY 86 originate Network Directed Broadcast packets. A router MAY have a 87 configuration option to allow it to receive directed broadcast 88 packets, however this option MUST be disabled by default, and thus 89 the router MUST NOT receive Network Directed Broadcast packets 90 unless specifically configured by the end user. 92 Section 5.3.5.2, second paragraph replaced with: 94 A router MAY have an option to enable receiving network-prefix- 95 directed broadcasts on an interface and MAY have an option to 96 enable forwarding network-prefix-directed broadcasts. These 97 options MUST default to blocking receipt and blocking forwarding 98 of network-prefix-directed broadcasts. 100 4. Security Considerations 102 The goal of this document is to reduce the efficacy of certain types 103 of denial of service attacks. 105 5. References 107 [1] F. Baker, "Requirements for IP Version 4 Routers", RFC1812, June 108 1995. 110 [2] P. Ferguson, D. Senie, "Ingress Filtering", RFC 2267, January 111 1998. 113 [3] See the pages by Craig Huegen at: 114 http://www.quadrunner.com/~chuegen/smurf.txt. 116 [4] C. Perkins, "IP Mobility Support", RFC 2002, October 1996. 118 [5] P. Calhoun, C. Perkins, "Mobile IP Dynamic Home Address 119 Allocation Extensions", , 120 Work in progress, November 1998. 122 6. Acknowledgements 124 The author would like to thank Brandon Ross of Mindspring and Gabriel 125 Montenegro of Sun for their input. 127 6. Author's Address 129 Daniel Senie 130 Amaranth Networks Inc. 131 324 Still River Road 132 Bolton, MA 01740 134 Phone: (978) 779-6813 136 EMail: dts@senie.com