Movatterモバイル変換

Internet Engineering Task Force (IETF)                         A. DurandRequest for Comments: 6302                              Juniper NetworksBCP: 162                                                    I. GashinskyCategory: Best Current Practice                              Yahoo! Inc.ISSN: 2070-1721                                                   D. Lee                                                          Facebook, Inc.                                                             S. Sheppard                                                                ATT Labs                                                               June 2011Logging Recommendations for Internet-Facing ServersAbstract   In the wake of IPv4 exhaustion and deployment of IP address sharing   techniques, this document recommends that Internet-facing servers log   port number and accurate timestamps in addition to the incoming IP   address.Status of This Memo   This memo documents an Internet Best Current Practice.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   BCPs is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6302.Copyright Notice   Copyright (c) 2011 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.Durand, et al.            Best Current Practice                 [Page 1]

RFC 6302             Internet-Facing Server Logging            June 2011Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .22.  Recommendations . . . . . . . . . . . . . . . . . . . . . . . .33.  ISP Considerations  . . . . . . . . . . . . . . . . . . . . . .44.  Security Considerations . . . . . . . . . . . . . . . . . . . .45.  References  . . . . . . . . . . . . . . . . . . . . . . . . . .45.1.  Normative references  . . . . . . . . . . . . . . . . . . .45.2.  Informative references  . . . . . . . . . . . . . . . . . .41.  Introduction   The global IPv4 address free pool at IANA was exhausted in February   2011.  Service providers will now have a hard time finding enough   IPv4 global addresses to sustain product and subscriber growth.  Due   to the huge existing global infrastructure, both hardware and   software, vendors, and service providers must continue to support   IPv4 technologies for the foreseeable future.  As legacy applications   and hardware are retired, the reliance on IPv4 will diminish;   however, this is a process that will take years, perhaps decades.   To maintain legacy IPv4 address support, service providers will have   little choice but to share IPv4 global addresses among multiple   customers.  Techniques to do so are outside of the scope of this   document.  All include some form of address translation/address   sharing, being NAT44 [RFC3022], NAT64 [RFC6146] or DS-Lite [DS-LITE].   The effects on the Internet of the introduction of those address   sharing techniques have been documented in [RFC6269].   Address sharing techniques come with their own logging infrastructure   to track the relation between which original IP address and source   port(s) were associated with which user and external IPv4 address at   any given point in time.  In the past, to support abuse mitigation or   public safety requests, the knowledge of the external global IP   address was enough to identify a subscriber of interest.  With   address sharing technologies, only providing information about the   external public address associated with a session to a service   provider is no longer sufficient information to unambiguously   identify customers.   Note: This document provides recommendations for Internet-facing   servers logging incoming connections.  It does not provide any   recommendations about logging on carrier-grade NAT or other address   sharing tools.Durand, et al.            Best Current Practice                 [Page 2]

RFC 6302             Internet-Facing Server Logging            June 20112.  Recommendations   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 inRFC 2119 [RFC2119].   It is RECOMMENDED as best current practice that Internet-facing   servers logging incoming IP addresses from inbound IP traffic also   log:   o  The source port number.   o  A timestamp, RECOMMENDED in UTC, accurate to the second, from a      traceable time source (e.g., NTP [RFC5905]).   o  The transport protocol (usually TCP or UDP) and destination port      number, when the server application is defined to use multiple      transports or multiple ports.   Discussion: Carrier-grade NATs may have different policies to recycle   ports; some implementations may decide to reuse ports almost   immediately, some may wait several minutes before marking the port   ready for reuse.  As a result, servers have no idea how fast the   ports will be reused and, thus, should log timestamps using a   reasonably accurate clock.  At this point, the RECOMMENDED accuracy   for timestamps is to the second or better.  Representation of   timestamps in UTC is preferred to local time with UTC-offset or time   zone, as this extra information can be lost in the reporting chain.   Examples of Internet-facing servers include, but are not limited to,   web servers and email servers.   Although the deployment of address sharing techniques is not foreseen   in IPv6, the above recommendations apply to both IPv4 and IPv6, if   only for consistency and code simplification reasons.   Discussions about data-retention policies are out of scope for this   document.  Server security and transport security are important for   the protection of logs for Internet-facing systems.  The operator of   the Internet-facing server must consider the risks, including the   data and services on the server, to determine the appropriate   measures.  The protection of logs is critical in incident   investigations.  If logs are tampered with, evidence could be   destroyed.   The above recommendations also apply to devices such as load-   balancers logging incoming connections on behalf of actual servers.Durand, et al.            Best Current Practice                 [Page 3]

RFC 6302             Internet-Facing Server Logging            June 2011   The above recommendations apply to current logging practices.  They   do not require any changes in the way logging is performed; e.g.,   which packets are examined and logged.3.  ISP Considerations   ISP deploying IP address sharing techniques should also deploy a   corresponding logging architecture to maintain records of the   relation between a customer's identity and IP/port resources   utilized.  However, recommendations on this topic are out of scope   for this document.4.  Security Considerations   In the absence of the source port number and accurate timestamp   information, operators deploying any address sharing techniques will   not be able to identify unambiguously customers when dealing with   abuse or public safety queries.5.  References5.1.  Normative references   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.5.2.  Informative references   [DS-LITE]  Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-              Stack Lite Broadband Deployments Following IPv4              Exhaustion", Work in Progress, May 2011.   [RFC3022]  Srisuresh, P. and K. Egevang, "Traditional IP Network              Address Translator (Traditional NAT)",RFC 3022,              January 2001.   [RFC5905]  Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network              Time Protocol Version 4: Protocol and Algorithms              Specification",RFC 5905, June 2010.   [RFC6146]  Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful              NAT64: Network Address and Protocol Translation from IPv6              Clients to IPv4 Servers",RFC 6146, April 2011.   [RFC6269]  Ford, M., Ed., Boucadair, M., Durand, A., Levis, P., and              P. Roberts, "Issues with IP Address Sharing",RFC 6269,              June 2011.Durand, et al.            Best Current Practice                 [Page 4]

RFC 6302             Internet-Facing Server Logging            June 2011Authors' Addresses   Alain Durand   Juniper Networks   1194 North Mathilda Avenue   Sunnyvale, CA  94089-1206   USA   EMail: adurand@juniper.net   Igor Gashinsky   Yahoo! Inc.   45 West 18th St.   New York, NY  10011   USA   EMail: igor@yahoo-inc.com   Donn Lee   Facebook, Inc.   1601 S. California Ave.   Palo Alto, CA  94304   USA   EMail: donn@fb.com   Scott Sheppard   ATT Labs   575 Morosgo Ave, 4d57   Atlanta, GA  30324   USA   EMail: Scott.Sheppard@att.comDurand, et al.            Best Current Practice                 [Page 5]