Recommendations on Filtering of IPv4 Packets Containing IPv4 Options
RFC 7126

Internet Engineering Task Force (IETF)                           F. Gont
Request for Comments: 7126                        UTN-FRH / SI6 Networks
BCP: 186                                                     R. Atkinson
Category: Best Current Practice                               Consultant
ISSN: 2070-1721                                             C. Pignataro
                                                                   Cisco
                                                           February 2014

  Recommendations on Filtering of IPv4 Packets Containing IPv4 Options

Abstract

   This document provides advice on the filtering of IPv4 packets based
   on the IPv4 options they contain.  Additionally, it discusses the
   operational and interoperability implications of dropping packets
   based on the IP options they contain.

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 has been approved for publication by the Internet
   Engineering Steering Group (IESG).  Further information on BCPs is
   available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7126.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 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.

Gont, et al.              Best Current Practice                 [Page 1]
RFC 7126            Filtering of IP-Optioned Packets       February 2014

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology and Conventions Used in This Document . . . .   3
     1.2.  Operational Focus . . . . . . . . . . . . . . . . . . . .   4
   2.  IP Options  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  General Security Implications of IP Options . . . . . . . . .   5
     3.1.  Processing Requirements . . . . . . . . . . . . . . . . .   5
   4.  Advice on the Handling of Packets with Specific IP Options  .   7
     4.1.  End of Option List (Type = 0) . . . . . . . . . . . . . .   7
     4.2.  No Operation (Type = 1) . . . . . . . . . . . . . . . . .   7
     4.3.  Loose Source and Record Route (LSRR) (Type = 131) . . . .   8
     4.4.  Strict Source and Record Route (SSRR) (Type = 137)  . . .  10
     4.5.  Record Route (Type = 7) . . . . . . . . . . . . . . . . .  11
     4.6.  Stream Identifier (Type = 136) (obsolete) . . . . . . . .  12
     4.7.  Internet Timestamp (Type = 68)  . . . . . . . . . . . . .  13
     4.8.  Router Alert (Type = 148) . . . . . . . . . . . . . . . .  14
     4.9.  Probe MTU (Type = 11) (obsolete)  . . . . . . . . . . . .  15
     4.10. Reply MTU (Type = 12) (obsolete)  . . . . . . . . . . . .  16
     4.11. Traceroute (Type = 82)  . . . . . . . . . . . . . . . . .  16
     4.12. DoD Basic Security Option (Type = 130)  . . . . . . . . .  17
     4.13. DoD Extended Security Option (Type = 133) . . . . . . . .  20
     4.14. Commercial IP Security Option (CIPSO) (Type = 134)  . . .  22
     4.15. VISA (Type = 142) . . . . . . . . . . . . . . . . . . . .  23
     4.16. Extended Internet Protocol (Type = 145) . . . . . . . . .  24
     4.17. Address Extension (Type = 147)  . . . . . . . . . . . . .  25
     4.18. Sender Directed Multi-Destination Delivery (Type = 149) .  25
     4.19. Dynamic Packet State (Type = 151) . . . . . . . . . . . .  26
     4.20. Upstream Multicast Pkt. (Type = 152)  . . . . . . . . . .  26
     4.21. Quick-Start (Type = 25) . . . . . . . . . . . . . . . . .  27
     4.22. RFC3692-Style Experiment (Types = 30, 94, 158, and 222) .  28
     4.23. Other IP Options  . . . . . . . . . . . . . . . . . . . .  29
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  31
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  31
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  31
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  31
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  32

Gont, et al.              Best Current Practice                 [Page 2]