draft-ietf-v6ops-v6nd-problems-03.txt   draft-ietf-v6ops-v6nd-problems-04.txt 
v6ops I. Gashinsky v6ops I. Gashinsky
Internet-Draft Yahoo! Internet-Draft Yahoo!
Intended status: Informational J. Jaeggli Intended status: Informational J. Jaeggli
Expires: July 28, 2012 Zynga Expires: August 5, 2012 Zynga
W. Kumari W. Kumari
Google Inc Google Inc
January 25, 2012 February 02, 2012
Operational Neighbor Discovery Problems Operational Neighbor Discovery Problems
draft-ietf-v6ops-v6nd-problems-03 draft-ietf-v6ops-v6nd-problems-04
Abstract Abstract
In IPv4, subnets are generally small, made just large enough to cover In IPv4, subnets are generally small, made just large enough to cover
the actual number of machines on the subnet. In contrast, the the actual number of machines on the subnet. In contrast, the
default IPv6 subnet size is a /64, a number so large it covers default IPv6 subnet size is a /64, a number so large it covers
trillions of addresses, the overwhelming number of which will be trillions of addresses, the overwhelming number of which will be
unassigned. Consequently, simplistic implementations of Neighbor unassigned. Consequently, simplistic implementations of Neighbor
Discovery (ND) can be vulnerable to deliberate or accidental denial Discovery (ND) can be vulnerable to deliberate or accidental denial
of service, whereby they attempt to perform address resolution for of service, whereby they attempt to perform address resolution for
skipping to change at page 2, line 4 skipping to change at page 2, line 4
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 28, 2012. This Internet-Draft will expire on August 5, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 7, line 33 skipping to change at page 7, line 33
existing entries in the neighbor cache, and unable to answer Neighbor existing entries in the neighbor cache, and unable to answer Neighbor
Solicitation). This condition can result in the inability to resolve Solicitation). This condition can result in the inability to resolve
new neighbors and loss of reachability to neighbors with existing ND- new neighbors and loss of reachability to neighbors with existing ND-
Cache entries. During testing it was concluded that 4 simultaneous Cache entries. During testing it was concluded that 4 simultaneous
nmap sessions from a low-end computer was sufficient to make a nmap sessions from a low-end computer was sufficient to make a
router's neighbor discovery process unusable and therefore forwarding router's neighbor discovery process unusable and therefore forwarding
became unavailable to the destination subnets. became unavailable to the destination subnets.
The failure to maintain proper NDP behavior whilst under attack has The failure to maintain proper NDP behavior whilst under attack has
been observed across multiple platforms and implementations, been observed across multiple platforms and implementations,
including the largest routers available (when this document was including the largest modern router platforms available (at the
started) from two of the largest vendors. inception of work on this document).
5. Neighbor Discovery Overview 5. Neighbor Discovery Overview
When a packet arrives at (or is generated by) a router for a When a packet arrives at (or is generated by) a router for a
destination on an attached link, the router needs to determine the destination on an attached link, the router needs to determine the
correct link-layer address to use in the destination field of the correct link-layer address to use in the destination field of the
layer 2 encapsulation. The router checks the Neighbor Cache for an layer 2 encapsulation. The router checks the Neighbor Cache for an
existing Neighbor Cache Entry for the neighbor, and if none exists, existing Neighbor Cache Entry for the neighbor, and if none exists,
invokes the address resolution portions of the IPv6 Neighbor invokes the address resolution portions of the IPv6 Neighbor
Discovery [RFC4861] protocol to determine the link-layer address of Discovery [RFC4861] protocol to determine the link-layer address of
skipping to change at page 12, line 20 skipping to change at page 12, line 20
No IANA resources or consideration are requested in this draft. No IANA resources or consideration are requested in this draft.
9. Security Considerations 9. Security Considerations
This document outlines mitigation options that operators can use to This document outlines mitigation options that operators can use to
protect themselves from Denial of Service attacks. Implementation protect themselves from Denial of Service attacks. Implementation
advice to router vendors aimed at ameliorating known problems carries advice to router vendors aimed at ameliorating known problems carries
the risk of previously unforeseen consequences. It is not believed the risk of previously unforeseen consequences. It is not believed
that these mitigation techniques or the implementation of finer- that these mitigation techniques or the implementation of finer-
grained queuing of NDP activity create additional security risks or grained queuing of NDP activity create additional security risks or
DoS exposure. DOS exposure.
10. Acknowledgements 10. Acknowledgements
The authors would like to thank Ron Bonica, Troy Bonin, John Jason The authors would like to thank Ron Bonica, Troy Bonin, John Jason
Brzozowski, Randy Bush, Vint Cerf, Tassos Chatzithomaoglou, Jason Brzozowski, Randy Bush, Vint Cerf, Tassos Chatzithomaoglou, Jason
Fesler, Wes George, Erik Kline, Jared Mauch, Chris Morrow and Suran Fesler, Wes George, Erik Kline, Jared Mauch, Chris Morrow and Suran
De Silva. Special thanks to Thomas Narten and Ray Hunter for De Silva. Special thanks to Thomas Narten and Ray Hunter for
detailed review and (even more so) for providing text! detailed review and (even more so) for providing text!
Apologies for anyone we may have missed; it was not intentional. Apologies for anyone we may have missed; it was not intentional.
 End of changes. 6 change blocks. 
7 lines changed or deleted 7 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/