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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-11) exists of draft-ietf-softwire-dual-stack-lite-07 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force A. Durand 3 Internet-Draft Juniper Networks 4 Intended status: BCP I. Gashinsky 5 Expires: October 21, 2011 Yahoo! Inc. 6 D. Lee 7 Facebook, Inc. 8 S. Sheppard 9 ATT Labs 10 April 19, 2011 12 Logging recommendations for Internet facing servers 13 draft-ietf-intarea-server-logging-recommendations-04 15 Abstract 17 In the wake of IPv4 exhaustion and deployment of IP address sharing 18 techniques, this document recommends that Internet facing servers log 19 port number and accurate timestamps in addition to the incoming IP 20 address. 22 Status of this Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on October 21, 2011. 39 Copyright Notice 41 Copyright (c) 2011 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 57 2. Recommendations . . . . . . . . . . . . . . . . . . . . . . . . 3 58 3. ISP Considerations . . . . . . . . . . . . . . . . . . . . . . 4 59 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 60 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 61 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 62 6.1. Normative references . . . . . . . . . . . . . . . . . . . 5 63 6.2. Informative references . . . . . . . . . . . . . . . . . . 5 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 66 1. Introduction 68 The global IPv4 address free pool at IANA was exhausted in February 69 2011. Service providers will now have a hard time finding enough 70 IPv4 global addresses to sustain product and subscriber growth. Due 71 to the huge global existing infrastructure, both hardware and 72 software, vendors and service providers must continue to support IPv4 73 technologies for the foreseeable future. As legacy applications and 74 hardware are retired the reliance on IPv4 will diminish but this is a 75 years long perhaps decades long process. 77 To maintain legacy IPv4 address support, service providers will have 78 little choice but to share IPv4 global addresses among multiple 79 customers. Techniques to do so are outside of the scope of this 80 document. All include some form of address translation/address 81 sharing, being NAT44 [RFC3022], NAT64 82 [I-D.ietf-behave-v6v4-xlate-stateful] or DS-Lite 83 [I-D.ietf-softwire-dual-stack-lite]. 85 The effects on the Internet of the introduction of those address 86 sharing techniques have been documented in 87 [I-D.ietf-intarea-shared-addressing-issues]. 89 Address sharing techniques come with their own logging infrastructure 90 to track the relation between which original IP address and source 91 port(s) were associated with which user and external IPv4 address at 92 any given point in time. In the past to support abuse mitigation or 93 public safety requests, the knowledge of the external global IP 94 address was enough to identify a subscriber of interest. With 95 address sharing technologies, only providing information about the 96 external public address associated with a session to a service 97 provider is no longer sufficient information to unambiguously 98 identify customers. 100 Note: this document provides recommendations for Internet facing 101 servers logging incoming connections. It does not provide any 102 recommendations about logging on carrier-grade NAT or other address 103 sharing tools. 105 2. Recommendations 107 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 108 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 109 document are to be interpreted as described in RFC 2119 [RFC2119]. 111 It is RECOMMENDED as best current practice that Internet facing 112 servers logging incoming IP addresses from inbound IP traffic also 113 log: 115 o The source port number. 117 o A timestamp, RECOMMENDED in UTC, accurate to the second, from a 118 traceable time source (e.g., NTP [RFC5905]). 120 o The transport protocol (usually TCP or UDP) and destination port 121 number, when the server application is defined to use multiple 122 transports or multiple ports. 124 Discussion: Carrier-grade NATs may have different policies to recycle 125 ports, some implementations may decide to reuse ports almost 126 immediately, some may wait several minutes before marking the port 127 ready for reuse. As a result, servers have no idea how fast the 128 ports will be reused and, thus, should log timestamps using a 129 reasonably accurate clock. At this point the RECOMMENDED accuracy 130 for timestamps is to the second or better. Representation of 131 timestamps in UTC is prefered to localtime with UTC-offset or time 132 zone as this extra information can be lost in the reporting chain. 134 Examples of Internet facing servers include, but are not limited to, 135 web servers and email servers. 137 Although the deployment of address sharing techniques is not foreseen 138 in IPv6, the above recommendations apply to both IPv4 and IPv6, if 139 only for consistency and code simplification reasons. 141 Discussions about data retention policies are out of scope for this 142 document. Server security and transport security is important for 143 the protection of logs for Internet facing systems. The operator of 144 the Internet facing server must consider the risks, including the 145 data and services on the server to determine the appropriate 146 measures. The protection of logs is critical in incident 147 investigations. If logs are tampered with, evidence could be 148 destroyed. 150 The above recommendations also apply to devices such as load- 151 balancers logging incoming connections on behalf of actual servers. 153 The above recommendations apply to current logging practices. They 154 do not require any changes in the way logging is performed; e.g., 155 which packets are examined and logged. 157 3. ISP Considerations 159 ISP deploying IP address sharing techniques should also deploy a 160 corresponding logging architecture to maintain records of the 161 relation between a customer's identity and IP/port resources 162 utilized. However, recommendations on this topic are out of scope 163 for this document. 165 4. IANA Considerations 167 None. 169 5. Security Considerations 171 In the absence of source port number and accurate timestamp, 172 operators deploying any address sharing techniques will not be able 173 to identify unambiguously customers when dealing with abuse or public 174 safety queries. 176 6. References 178 6.1. Normative references 180 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 181 Requirement Levels", BCP 14, RFC 2119, March 1997. 183 6.2. Informative references 185 [I-D.ietf-behave-v6v4-xlate-stateful] 186 Bagnulo, M., Matthews, P., and I. Beijnum, "Stateful 187 NAT64: Network Address and Protocol Translation from IPv6 188 Clients to IPv4 Servers", 189 draft-ietf-behave-v6v4-xlate-stateful-12 (work in 190 progress), July 2010. 192 [I-D.ietf-intarea-shared-addressing-issues] 193 Ford, M., Boucadair, M., Durand, A., Levis, P., and P. 194 Roberts, "Issues with IP Address Sharing", 195 draft-ietf-intarea-shared-addressing-issues-05 (work in 196 progress), March 2011. 198 [I-D.ietf-softwire-dual-stack-lite] 199 Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 200 Stack Lite Broadband Deployments Following IPv4 201 Exhaustion", draft-ietf-softwire-dual-stack-lite-07 (work 202 in progress), March 2011. 204 [RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network 205 Address Translator (Traditional NAT)", RFC 3022, 206 January 2001. 208 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 209 Time Protocol Version 4: Protocol and Algorithms 210 Specification", RFC 5905, June 2010. 212 Authors' Addresses 214 Alain Durand 215 Juniper Networks 216 1194 North Mathilda Avenue 217 Sunnyvale, CA 94089-1206 218 USA 220 Email: adurand@juniper.net 222 Igor Gashinsky 223 Yahoo! Inc. 224 45 West 18th St. 225 New York, NY 10011 226 USA 228 Email: igor@yahoo-inc.com 230 Donn Lee 231 Facebook, Inc. 232 1601 S. California Ave. 233 Palo Alto, CA 94304 234 USA 236 Email: donn@fb.com 238 Scott Sheppard 239 ATT Labs 240 575 Morosgo Ave, 4d57 241 Atlanta, GA 30324 242 USA 244 Email: Scott.Sheppard@att.com