draft-ietf-opsec-lla-only-04.txt   draft-ietf-opsec-lla-only-05.txt 
OPsec Working Group M. Behringer OPsec Working Group M. Behringer
Internet-Draft E. Vyncke Internet-Draft E. Vyncke
Intended status: Informational Cisco Intended status: Informational Cisco
Expires: April 23, 2014 October 20, 2013 Expires: June 5, 2014 December 2, 2013
Using Only Link-Local Addressing Inside an IPv6 Network Using Only Link-Local Addressing Inside an IPv6 Network
draft-ietf-opsec-lla-only-04 draft-ietf-opsec-lla-only-05
Abstract Abstract
In an IPv6 network it is possible to use only link-local addresses on In an IPv6 network it is possible to use only link-local addresses on
infrastructure links between routers. This document discusses the infrastructure links between routers. This document discusses the
advantages and disadvantages of this approach to help the decision advantages and disadvantages of this approach to help the decision
process for a given network. process for a given network.
Status of This Memo Status of This Memo
skipping to change at page 1, line 33 skipping to change at page 1, line 33
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This Internet-Draft will expire on April 23, 2014. This Internet-Draft will expire on June 5, 2014.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Using Link-Local Address on Infrastructure Links . . . . . . 2 2. Using Link-Local Address on Infrastructure Links . . . . . . 2
2.1. The Approach . . . . . . . . . . . . . . . . . . . . . . 3 2.1. The Approach . . . . . . . . . . . . . . . . . . . . . . 2
2.2. Advantages . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Advantages . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Caveats . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Caveats . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Internet Exchange Points . . . . . . . . . . . . . . . . 5 2.4. Internet Exchange Points . . . . . . . . . . . . . . . . 6
2.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Security Considerations . . . . . . . . . . . . . . . . . . . 7 3. Security Considerations . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
6. Informative References . . . . . . . . . . . . . . . . . . . 7 6. Informative References . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
An infrastructure link between a set of routers typically does not An infrastructure link between a set of routers typically does not
require global or even unique local addressing [RFC4193]. Using only require global or unique local addresses [RFC4193]. Using only link-
link-local addressing on such links has a number of advantages, for local addressing on such links has a number of advantages. For
example that routing tables do not need to carry link addressing, and example, that routing tables do not need to carry link addressing,
can therefore be significantly smaller. This helps to decrease and can therefore be significantly smaller. This helps to decrease
failover times in certain routing convergence events. An interface failover times in certain routing convergence events. An interface
of a router is also not reachable beyond the link boundaries, of a router is also not reachable beyond the link boundaries,
therefore reducing the attack horizon. therefore reducing the attack horizon.
This document discusses the advantages and caveats of this approach. This document discusses the advantages and caveats of this approach.
Note: [RFC6860] describes another approach for OPSFv2 and OSPFv3 by
modifying the existing protocols while this document does not modify
any protocol but works only for IPv6.
2. Using Link-Local Address on Infrastructure Links 2. Using Link-Local Address on Infrastructure Links
This document discusses the approach of using only link-local This document discusses the approach of using only link-local
addresses (LLA) on all router interfaces on infrastructure links. addresses (LLA) on all router interfaces on infrastructure links.
Routers typically need to receive packets neither from hosts, nor Routers don't typically need to receive packets from hosts or nodes
from nodes outside the network. For an network operator there may be outside the network. For a network operator, there may be reasons to
reasons to use greater than link-local scope addresses on use greater than link-local scope addresses on infrastructure
infrastructure interfaces for certain operational tasks, for example interfaces for certain operational tasks, such as pings to an
pings to an interface or traceroutes across the network. This interface or traceroutes across the network. This document discusses
document discusses such cases and proposes alternative procedures. such cases and proposes alternative procedures.
2.1. The Approach 2.1. The Approach
Neither global IPv6 addresses nor unique local addresses are In this approach neither globally routed IPv6 addresses nor unique
configured on infrastructure links. In the absence of specific local addresses are configured on infrastructure links. In the
global or unique local address definitions, the default behavior of absence of specific global or unique local address definitions, the
routers is to use link-local addresses notably for routing protocols. default behavior of routers is to use link-local addresses notably
for routing protocols.
The sending of ICMPv6 [RFC4443] error messages (packet-too-big, time- The sending of ICMPv6 [RFC4443] error messages (packet-too-big, time-
exceeded...) is required for routers, therefore another interface exceeded...) is required for routers. Therefore, another interface
must be configured with an IPv6 address with a greater scope than must be configured with an IPv6 address with a greater scope than
link-local. This will usually be a loopback interface with a global link-local. This address will usually be a loopback interface with a
scope address belonging to the operator and part of an announced global scope address belonging to the operator and part of an
prefix (with a suitable prefix length) to avoid being dropped by announced prefix (with a suitable prefix length) to avoid being
other routers implementing [RFC3704]. For the remainder of this dropped by other routers implementing [RFC3704]. This is
document we will refer to this interface as a "loopback interface". implementation dependent. For the remainder of this document we will
[RFC6724] mandates that greater than link-local scope IPv6 addresses refer to this interface as a "loopback interface".
must be used as the source IPv6 address for all generated ICMPv6
messages sent to a non link-local address. [RFC6724] recommends that greater than link-local scope IPv6
addresses are used as the source IPv6 address for all generated
ICMPv6 messages sent to a non link-local address, with the exception
of ICMPv6 redirect messages, as defined in [RFC4861] section 4.5.
The effect on specific traffic types is as follows: The effect on specific traffic types is as follows:
o Control plane protocols, such as BGP [RFC4271], ISIS [IS-IS], o Most control plane protocols, such as BGP [RFC4271], ISIS [IS-IS],
OSPFv3 [RFC5340], RIPng [RFC2080], PIM [RFC4609] work by default OSPFv3 [RFC5340], RIPng [RFC2080], PIM [RFC4609] work by default
or can be configured to work with link-local addresses. or can be configured to work with link-local addresses.
Exceptions are explained in the caveats section (Section 2.3).
o Management plane traffic, such as SSH [RFC4251], Telnet [RFC0495], o Management plane traffic, such as SSH [RFC4251], Telnet [RFC0495],
SNMP [RFC1157], and ICMP echo request [RFC4443], can use as SNMP [RFC1157], and ICMPv6 echo request [RFC4443], can use the
destination address the address of the router loopback interface. address of the router loopback interface as the destination
Router management can also be done over out-of-band channels. address. Router management can also be done over out-of-band
channels.
o ICMP error message can be sourced from a loopback interface. They o ICMP error messages are usually sourced from a loopback interface
must not be sourced from link-local addresses when the destination with a greater than link-local address scope. [RFC4861] section
is non link-local. See [RFC6724]. 4.5 explains one exception: ICMP redirect messages can also be
sourced from a link-local address.
o Data plane traffic is forwarded independently of the link address o Data plane traffic is forwarded independently of the link address
type. type.
o Neighbor discovery (neighbor solicitation and neighbor o Neighbor discovery (neighbor solicitation and neighbor
advertisement) is done by using link-local unicast and multicast advertisement) is done by using link-local unicast and multicast
addresses, therefore neighbor discovery is not affected. addresses. Therefore neighbor discovery is not affected.
We therefore conclude that it is possible to construct a working We therefore conclude that it is possible to construct a working
network in this way. network in this way.
2.2. Advantages 2.2. Advantages
The following list of advantages is in no particular order.
Smaller routing tables: Since the routing protocol only needs to Smaller routing tables: Since the routing protocol only needs to
carry one global address (the loopback interface) per router, it is carry one global address (the loopback interface) per router, it is
smaller than the traditional approach where every infrastructure link smaller than the traditional approach where every infrastructure link
addresses are carried in the routing protocol. This reduces memory address is carried in the routing protocol. This reduces memory
consumption, and increases the convergence speed in some routing consumption, and increases the convergence speed in some routing
failover cases (notably because the Forwarding Information Base to be failover cases. Because the Forwarding Information Base to be
downloaded to line cards is smaller but also because there are less downloaded to line cards is smaller and there are fewer prefixes in
prefixes in the Routing Information Base hence accelerating the the Routing Information Base, the routing algorithm is accellerated.
routing algorithm). Note: smaller routing tables can also be Note: smaller routing tables can also be achieved by putting
achieved by putting interfaces in passive mode for the IGP. interfaces in passive mode for the Interior Gateway Protocol (IGP).
Simpler address management: Only loopback interface addresses need to
be considered in an addressing plan. This also allows for easier
renumbering.
Lower configuration complexity: link-local addresses require no
specific configuration, thereby lowering the complexity and size of
router configurations. This also reduces the likelihood of
configuration mistakes.
Simpler DNS: Less routable address space in use also means less
reverse and forward mapping DNS resource records to maintain.
Reduced attack surface: Every routable address on a router Reduced attack surface: Every routable address on a router
constitutes a potential attack point: a remote attacker can send constitutes a potential attack point: a remote attacker can send
traffic to that address, for example a TCP SYN flood (see [RFC4987]), traffic to that address. Examples are a TCP SYN flood (see
or can attempt SSH brute force password attacks. If a network only [RFC4987]), or SSH brute force password attacks. If a network only
uses the addresses of the router loopback interface(s), only those uses the addresses of the router loopback interface(s), only those
need to be protected from outside the network. This may ease addresses need to be protected from outside the network. This may
protection measures, such as infrastructure access control lists. ease protection measures, such as infrastructure access control
lists.
Without using link-local addresses, it is still possible to achieve Without using link-local addresses, it is still possible to achieve
the same result if the network addressing scheme is set up such that the same result if the network addressing scheme is set up such that
all link and loopback interfaces have greater than link-local all link and loopback interfaces have greater than link-local
addresses and are aggregatable, and if the infrastructure access list addresses and are aggregatable, and if the infrastructure access list
covers that entire aggregated space. See also [RFC6752] for further covers that entire aggregated space. See also [RFC6752] for further
discussion on this topic. discussion on this topic.
Lower configuration complexity: link-local addresses require no [RFC6860] describes another approach to hide addressing on
specific configuration, thereby lowering the complexity and size of infrastructure links for OSPFv2 and OSPFv3, by modifying the existing
router configurations. This also reduces the likelihood of protocols. This document does not modify any protocol, however it
configuration mistakes. works only for IPv6.
Simpler DNS: Less routable address space in use also means less
reverse and forward mapping DNS resource records to maintain.
2.3. Caveats 2.3. Caveats
The caveats listed in this section are in no particular order.
Interface ping: if an interface doesn't have a routable address, it Interface ping: if an interface doesn't have a routable address, it
can only be pinged from a node on the same link. Therefore it is not can only be pinged from a node on the same link. Therefore, it is
possible to ping a specific link interface remotely. A possible not possible to ping a specific link interface remotely. A possible
workaround is to ping the loopback address of a router instead. In workaround is to ping the loopback address of a router instead. In
most cases today it is not possible to see which link the packet was most cases today, it is not possible to see which link the packet was
received on; however, RFC5837 [RFC5837] suggests to include the received on; however, [RFC5837] suggests including the interface
interface identifier of the interface a packet was received on in the identifier of the interface a packet was received on in the ICMPv6
ICMP response; it must be noted that there are few implementions of response; it must be noted that there are few implementations of this
this ICMP extension. With this approach it would be possible to ping ICMPv6 extension. With this approach it would be possible to ping a
a router on the addresses of loopback interfaces, yet see which router on the addresses of loopback interfaces, yet see which
interface the packet was received on. To check liveliness of a interface the packet was received on. To check liveliness of a
specific interface it may be necessary to use other methods, for specific interface, it may be necessary to use other methods, such as
example to connect to the router via SSH and to check locally or use connecting to the router via SSH and checking locally or using SNMP.
SNMP.
Traceroute: similar to the ping case, a reply to a traceroute packet Traceroute: similar to the ping case, a reply to a traceroute packet
would come from the address of a loopback interface, and current would come from the address of a loopback interface, and current
implementations do not display the specific interface the packets implementations do not display the specific interface the packets
came in on. Also here, RFC5837 [RFC5837] provides a solution. came in on. Also here, [RFC5837] provides a solution. As in the
ping case above, it is not possible to traceroute to a particular
interface if it only has a link-local address.
Hardware dependency: LLAs are usually EUI-64 based, hence, they Hardware dependency: LLAs are usually EUI-64 based, hence, they
change when the MAC address is changed. This could pose problem in a change when the MAC address is changed. This could pose problem in a
case where the routing neighbor must be configured explicitly (e.g. case where the routing neighbor must be configured explicitly (e.g.
BGP) and a line card needs to be physically replaced hence changing BGP) and a line card needs to be physically replaced hence changing
the EUI-64 LLA and breaking the routing neighborship. But, LLAs can the EUI-64 LLA and breaking the routing neighborship. LLAs can be
be statically configured such as fe80::1 and fe80::2 which can be statically configured such as fe80::1 and fe80::2 which can be used
used to configure any required static routing neighborship. This to configure any required static routing neighborship. However, this
static configuration is similar in complexity to statically static LLA configuration may be more complex to operate than
configured greater than link-local addresses, however, it is only statically configured greater than link-local addresses, because the
required where routing peers are explicitly configured. link scope must also be considered, as in this example: 'BGP neighbor
fe80::1%eth0 is down'.
Network Management System (NMS) toolkits: if there is any NMS tool Network Management System (NMS) toolkits: if there is any NMS tool
that makes use of interface IP address of a router to carry out any that makes use of interface IP address of a router to carry out any
of NMS functions, then it would no longer work, if the interface is of its NMS functions, then it would no longer work if the interface
missing routable address. A possible workaround for such tools is to does not have a routable address. A possible workaround for such
use the routable address of the router loopback interface instead. tools is to use the routable address of the router loopback interface
Most vendor implementations allow the specification of the address of instead. Most vendor implementations allow the specification of
the loopback interfaces for SYSLOG, IPfix, SNMP. LLDP (IEEE loopback interface addresses for SYSLOG, IPfix, and SNMP. The
802.1AB-2009) runs directly over Ethernet and does not require any protocol LLDP (IEEE 802.1AB-2009) runs directly over Ethernet and
IPv6 address so dynamic network discovery is not hindered when using does not require any IPv6 address, so dynamic network discovery is
LLDP. But, network discovery based on NDP cache content will only not hindered when using LLDP. But, network discovery based on NDP
display the link-local addresses and not the addresses of the cache content will only display the link-local addresses and not the
loopback interfaces; therefore, network discovery should rather be addresses of the loopback interfaces; therefore, network discovery
based on the Route Information Base to detect adjacent nodes. should rather be based on the Route Information Base to detect
adjacent nodes.
MPLS and RSVP-TE [RFC3209] allows establishing MPLS LSP on a path MPLS and RSVP-TE [RFC3209] allows establishing MPLS LSP on a path
that is explicitly identified by a strict sequence of IP prefixes or that is explicitly identified by a strict sequence of IP prefixes or
addresses (each pertaining to an interface or a router on the path). addresses (each pertaining to an interface or a router on the path).
This is commonly used for Fast Re-Route (FRR). However, if an This is commonly used for Fast Re-Route (FRR). However, if an
interface uses only a link-local address, then such LSPs cannot be interface uses only a link-local address, then such LSPs cannot be
established. At the time of writing this document, there is no established. At the time of writing this document, there is no
workaround for this case; therefore where RSVP-TE is being used, the workaround for this case; therefore, where RSVP-TE is being used, the
approach described in this document does not work. approach described in this document does not work.
2.4. Internet Exchange Points 2.4. Internet Exchange Points
Internet Exchange Points (IXPs) have a special importance in the Internet Exchange Points (IXPs) have a special importance in the
global Internet, because they connect a high number of networks in a global Internet, because they connect a high number of networks in a
single location, and because significant part of Internet traffic single location, and because a significant part of Internet traffic
pass through at least one IXP. An IXP with all the service provider passes through at least one IXP. An IXP requires therefore a very
nodes requires therefore a very high level of security. The address high level of security. The address space used on an IXP is
space used on an IXP is generally known, as it is registered in the generally known, as it is registered in the global Internet Route
global Internet Route Registry, or it is easily discoverable through Registry, or it is easily discoverable through traceroute. The IXP
traceroute. The IXP prefix is especially critical, because prefix is especially critical, because practically all addresses on
practically all addresses on this prefix are critical systems in the this prefix are critical systems in the Internet.
Internet.
Apart from general device security guidelines, there are generally Apart from general device security guidelines, there are generally
two additional ways to raise security (see also two additional ways to raise security (see also
[I-D.ietf-opsec-bgp-security]): [I-D.ietf-opsec-bgp-security]):
1. Not to announce the prefix in question, and 1. Not to announce the prefix in question, and
2. To drop all traffic destined to the IXP prefixes from traffic 2. To drop all traffic from remote locations destined to the IXP
from remote locations. prefixes.
Not announcing the prefix of the IXP however would frequently result Not announcing the prefix of the IXP would frequently result in
in traceroute and similar packets (required for PMTUd) to be dropped traceroute and similar packets (required for PMTUd) to be dropped due
due to uRPF checks. Given that PMTUd is critical, this is generally to uRPF checks. Given that PMTUd is critical, this is generally not
not acceptable. Dropping all external traffic to the IXP prefix is acceptable. Dropping all external traffic to the IXP prefix is hard
hard to implement, because if only one service provider on an IXP to implement, because if only one service provider connected to an
routes does not filter correctly, then all IXP routers are reachable IXP does not filter correctly, then all IXP routers are reachable
from at least that service provider network. from at least that service provider network.
As the prefix used in IXP is usually longer than a /48 it is As the prefix used in the IXP is usually longer than a /48, it is
frequently dropped by route filters on the Internet having the same frequently dropped by route filters on the Internet having the same
net effect as not announced the prefix. net effect as not announcing the prefix.
Using link-local addresses on the IXP may help in this scenario. In Using link-local addresses on the IXP may help in this scenario. In
this case, the generated ICMP packets would be generated from this case, the generated ICMPv6 packets would be generated from
loopback interfaces or from any other interfaces with globally loopback interfaces or from any other interface with a globally
routable sources without any configuration. However in this case, routable address without any configuration. However in this case,
each service provider would use his own address space, making a each service provider would use his own address space, making a
generic attack against all devices on the IXP harder. Also all the generic attack against all devices on the IXP harder. All of an
addresses of the loopback interfaces on the IXP can be discovered by IXP's loopback interface addresses can be discovered by a potential
a potential attacker by a simple traceroute; a generic attack is attacker with a simple traceroute; a generic attack is therefore
therefore still possible, but it would require more work. still possible, but it would require more work.
In some cases service providers carry the IXP addresses in their IGP In some cases service providers carry the IXP addresses in their IGP
for certain forms of traffic engineering across multiple exit points. for certain forms of traffic engineering across multiple exit points.
If link-local addresses are used, these cannot be used for this Link-local addresses cannot be used for this purpose; in this case,
purpose; in this case, the service provider would have to employ the service provider would have to employ other methods of traffic
other methods of traffic engineering. engineering.
If an Internet Exchange Point is using a global prefix registered for If an Internet Exchange Point is using a global prefix registered for
this purpose, a traceroute will indicate whether the trace crosses an this purpose, a traceroute will indicate whether the trace crosses an
IXP rather than a private interconnect. If link local addressing is IXP rather than a private interconnect. If link local addressing is
used instead, a traceroute will not provide this distinction. used instead, a traceroute will not provide this distinction.
2.5. Summary 2.5. Summary
Using link-local addressing only on infrastructure links has a number Using link-local addressing only on infrastructure links has a number
of advantages, such as a smaller routing table size and a reduced of advantages, such as a smaller routing table size and a reduced
attack surface. It also simplifies router configurations. However, attack surface. It also simplifies router configurations. However,
the way certain network management tasks are carried out today has to the way certain network management tasks are carried out today has to
be adapted to provide the same level of detail, for example interface be adapted to provide the same level of detail, for example interface
identifiers in traceroute. identifiers in traceroute.
3. Security Considerations 3. Security Considerations
Using LLAs only on infrastructure links reduces the attack surface of Using LLAs only on infrastructure links reduces the attack surface of
skipping to change at page 7, line 14 skipping to change at page 7, line 35
Using link-local addressing only on infrastructure links has a number Using link-local addressing only on infrastructure links has a number
of advantages, such as a smaller routing table size and a reduced of advantages, such as a smaller routing table size and a reduced
attack surface. It also simplifies router configurations. However, attack surface. It also simplifies router configurations. However,
the way certain network management tasks are carried out today has to the way certain network management tasks are carried out today has to
be adapted to provide the same level of detail, for example interface be adapted to provide the same level of detail, for example interface
identifiers in traceroute. identifiers in traceroute.
3. Security Considerations 3. Security Considerations
Using LLAs only on infrastructure links reduces the attack surface of Using LLAs only on infrastructure links reduces the attack surface of
a router: addresses of loopback interfaces with routed addresses are a router: loopback interfaces with routed addresses are still
still reachable and must be secured, but infrastructure links can reachable and must be secured, but infrastructure links can only be
only be attacked from the local link. This simplifies security of attacked from the local link. This simplifies security of control
control and management planes. The approach does not impact the and management planes. The approach does not impact the security of
security of the data plane. This approach does not address control the data plane. The link-local-only approach does not address
plane [RFC6192] attacks generated by data plane packets (such as hop- control plane [RFC6192] attacks generated by data plane packets (such
limit expiration or packets containing a hop-by-hop extension as hop-limit expiration or packets containing a hop-by-hop extension
header). header).
As in the traditional approach, this approach relies on the
assumption that all routers can be trusted due to physical and
operational security.
4. IANA Considerations 4. IANA Considerations
There are no IANA considerations or implications that arise from this There are no IANA considerations or implications that arise from this
document. document.
5. Acknowledgements 5. Acknowledgements
The authors would like to thank Salman Asadullah, Brian Carpenter, The authors would like to thank Salman Asadullah, Brian Carpenter,
Benoit Claise, Rama Darbha, Simon Eng, Wes George, Fernando Gont, Bill Cerveny, Benoit Claise, Rama Darbha, Simon Eng, Wes George,
Harald Michl, Janos Mohacsi, Alvaro Retana and Ivan Pepelnjak for Fernando Gont, Jen Linkova, Harald Michl, Janos Mohacsi, Ivan
their useful comments about this work. Pepelnjak, and Alvaro Retana for their useful comments about this
work.
6. Informative References 6. Informative References
[I-D.ietf-opsec-bgp-security] [I-D.ietf-opsec-bgp-security]
Durand, J., Pepelnjak, I., and G. Doering, "BGP operations Durand, J., Pepelnjak, I., and G. Doering, "BGP operations
and security", draft-ietf-opsec-bgp-security-01 (work in and security", draft-ietf-opsec-bgp-security-01 (work in
progress), July 2013. progress), July 2013.
[IS-IS] ISO/IEC 10589, ., "Intermediate System to Intermediate [IS-IS] ISO/IEC 10589, , "Intermediate System to Intermediate
System Intra-Domain Routing Exchange Protocol for use in System Intra-Domain Routing Exchange Protocol for use in
Conjunction with the Protocol for Providing the Conjunction with the Protocol for Providing the
Connectionless-mode Network Service (ISO 8473)", June Connectionless-mode Network Service (ISO 8473)", June
1992. 1992.
[RFC0495] McKenzie, A., "Telnet Protocol specifications", RFC 495, [RFC0495] McKenzie, A., "Telnet Protocol specifications", RFC 495,
May 1973. May 1973.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, September 1981. RFC 792, September 1981.
skipping to change at page 8, line 43 skipping to change at page 9, line 14
[RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control
Message Protocol (ICMPv6) for the Internet Protocol Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006. Version 6 (IPv6) Specification", RFC 4443, March 2006.
[RFC4609] Savola, P., Lehtonen, R., and D. Meyer, "Protocol [RFC4609] Savola, P., Lehtonen, R., and D. Meyer, "Protocol
Independent Multicast - Sparse Mode (PIM-SM) Multicast Independent Multicast - Sparse Mode (PIM-SM) Multicast
Routing Security Issues and Enhancements", RFC 4609, Routing Security Issues and Enhancements", RFC 4609,
October 2006. October 2006.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4987] Eddy, W., "TCP SYN Flooding Attacks and Common [RFC4987] Eddy, W., "TCP SYN Flooding Attacks and Common
Mitigations", RFC 4987, August 2007. Mitigations", RFC 4987, August 2007.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008. for IPv6", RFC 5340, July 2008.
[RFC5837] Atlas, A., Bonica, R., Pignataro, C., Shen, N., and JR. [RFC5837] Atlas, A., Bonica, R., Pignataro, C., Shen, N., and JR.
Rivers, "Extending ICMP for Interface and Next-Hop Rivers, "Extending ICMP for Interface and Next-Hop
Identification", RFC 5837, April 2010. Identification", RFC 5837, April 2010.
 End of changes. 45 change blocks. 
135 lines changed or deleted 155 lines changed or added

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