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Contents
- IPv6 Snooping
- Finding Feature Information
- Information About IPv6 Snooping
- IPv6 Snooping
- IPv6 Neighbor Discovery Inspection
- IPv6 Global Policies
- IPv6 ND Inspection
- IPv6 Device Tracking
- IPv6 First-Hop Security Binding Table
- IPv6 Device Tracking
- IPv6 Address Glean
- How to Configure IPv6 Snooping
- Configuring IPv6 Snooping
- Configuring IPv6 Neighbor Discovery Inspection
- Configuring IPv6 ND Inspection Globally
- Applying IPv6 ND Inspection on a Specified Interface
- Verifying and Troubleshooting IPv6 ND Inspection
- Configuring IPv6 Device Tracking
- Configuring the IPv6 Binding Table Content
- Configuring IPv6 Device Tracking
- Configuring IPv6 Address Glean
- Configuration Examples for IPv6 Snooping
- Example: Configuring IPv6 Snooping
- Example: IPv6 ND Inspection and RA Guard Configuration
- Example: IPv6 Device Tracking
- Example: Configuring IPv6 Address Glean
- Additional References
- Feature Information for IPv6 Snooping
- Glossary
IPv6 Snooping
The IPv6 snooping feature bundles several layer 2 IPv6 first-hop security features, including IPv6 neighbor discovery, IPv6 device tracking, and IPv6 address glean. IPv6 snooping operates at layer 2, or between layer 2 and layer 3, and provides IPv6 features with security and scalability.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About IPv6 Snooping
IPv6 Snooping
The IPv6 snooping feature bundles several layer 2 IPv6 first-hop security features, including IPv6 address glean, IPv6 device tracking, and IPv6 neighbor discovery. IPv6 snooping operates at layer 2, or between layer 2 and layer 3, and provides IPv6 features with security and scalability.
When IPv6 snooping is configured on a target (which vary depending on platform target support and may include device ports, switchports, layer 2 interfaces, layer 3 interfaces, and VLANs), capture instructions are downloaded to the hardware to redirect the neighbor discovery (ND) protocol and Dynamic Host Configuration Protocol (DHCP) for IPv6 traffic up to the switch integrated security features (SISF) infrastructure in the routing device. For ND traffic, messages such as NS; NA, RS, RA and REDIRECT are directed to SISF. For DHCP, UDP messages sourced from port 546 or 547 are redirected.
IPv6 snooping capture registers its "capture rules" to the classifier, which aggregates all rules from all features on a given target, and installs the corresponding ACL down into the platform-dependent modules. Upon receiving redirected traffic, the classifier calls all entry points from any registered feature (for the target on which the traffic is being received), including the IPv6 snooping entry point. The IPv6 snooping entry point is the last to be called, so any decision (such as drop) made by another feature supersedes the IPv6 snooping decision.
IPv6 Neighbor Discovery Inspection
IPv6 ND inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables. IPv6 ND inspection analyzes ND messages in order to build a trusted binding table. IPv6 ND messages that do not have valid bindings are dropped.
IPv6 Global Policies
IPv6 global policies provide storage and access policy database services. IPv6 neighbor discovery (ND) inspection and the IPv6 Router Advertisement (RA) Guard are IPv6 global policies features. Every time an ND inspection or RA guard is configured globally, the policy attributes are stored in the software policy database. The policy is then applied to an interface, and the software policy database entry is updated to include this interface to which the policy is applied.
IPv6 ND Inspection
IPv6 ND inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables. IPv6 ND inspection analyzes neighbor discovery messages in order to build a trusted binding table database, and IPv6 neighbor discovery messages that do not have valid bindings are dropped. A neighbor discovery message is considered trustworthy if its IPv6-to-MAC mapping is verifiable.
This feature mitigates some of the inherent vulnerabilities for the neighbor discovery mechanism, such as attacks on duplicate address detection (DAD), address resolution, device discovery, and the neighbor cache.
IPv6 Device Tracking
IPv6 device tracking provides IPv6 host liveness tracking so that a neighbor table can be immediately updated when an IPv6 host disappears.
IPv6 First-Hop Security Binding Table
A database table of IPv6 neighbors connected to the device is created from information sources such as Neighbor Discovery (ND) protocol snooping. This database, or binding, table is used by various IPv6 guard features to validate the link-layer address (LLA), the IPv4 or IPv6 address, and prefix binding of the neighbors to prevent spoofing and redirect attacks.
IPv6 Device Tracking
The IPv6 device tracking feature provides IPv6 host liveness tracking so that a neighbor table can be immediately updated when an IPv6 host disappears. The feature tracks the liveness of the neighbors connected through the Layer 2 device on regular basis in order to revoke network access privileges as they become inactive.
IPv6 Address Glean
The IPv6 address glean feature is the foundation for many other IPv6 features that depend on an accurate binding table. It inspects ND and DHCP messages on a link to glean addresses, and then populates the binding table with these addresses. This feature also enforces address ownership and limits the number of addresses any given node is allowed to claim.
The following figure shows how IPv6 address glean works.
How to Configure IPv6 Snooping
Configuring IPv6 Snooping
DETAILED STEPS
- Configuring IPv6 Neighbor Discovery Inspection
- Configuring IPv6 Device Tracking
- Configuring IPv6 Address Glean
Configuring IPv6 Neighbor Discovery Inspection
Configuring IPv6 ND Inspection Globally
DETAILED STEPS
Applying IPv6 ND Inspection on a Specified Interface
DETAILED STEPS
Verifying and Troubleshooting IPv6 ND Inspection
DETAILED STEPS
Configuring IPv6 Device Tracking
Configuring the IPv6 Binding Table Content
DETAILED STEPS
Configuring IPv6 Device Tracking
Perform this task to provide fine tuning for the life cycle of an entry in the binding table for the IPv6 device tracking feature For IPv6 device tracking to work, the binding table needs to be populated.
DETAILED STEPS
Configuring IPv6 Address Glean
 Note | You must configure an IPv6 snooping policy and attach the policy to a target before configuring IPv6 address glean. |
DETAILED STEPS
Configuration Examples for IPv6 Snooping
Example: Configuring IPv6 Snooping
Device(config)# ipv6 snooping policy policy1 Device(config-ipv6-snooping)# ipv6 snooping attach-policy policy1 Device(config-ipv6-snooping)# exit . . . Device# show ipv6 snooping policies policy1 Policy policy1 configuration: trusted-port device-role node Policy applied on the following interfaces: Et0/0 vlan all Et1/0 vlan all Policy applied on the following vlans: vlan 1-100,200,300-400
- Example: IPv6 ND Inspection and RA Guard Configuration
- Example: IPv6 Device Tracking
- Example: Configuring IPv6 Address Glean
Example: IPv6 ND Inspection and RA Guard Configuration
This example provides information about an interface on which both the neighbor discovery (ND) inspection and router advertisement (RA) guard features are configured:
Device# show ipv6 snooping capture-policy interface ethernet 0/0
Hardware policy registered on Ethernet 0/0
Protocol Protocol value Message Value Action Feature
ICMP 58 RS 85 punt RA Guard
punt ND Inspection
ICMP 58 RA 86 drop RA guard
punt ND Inspection
ICMP 58 NS 87 punt ND Inspection
ICM 58 NA 88 punt ND Inspection
ICMP 58 REDIR 89 drop RA Guard
punt ND Inspection
Example: IPv6 Device Tracking
Device# show ipv6 neighbor tracking
IPv6 address Link-Layer addr Interface vlan prlvl age state Time left
ND FE80::A8BB:CCFF:FE01:F500 AABB.CC01.F500 Et0/0 100 0002 0 REACHABLE 8850
L FE80::21D:71FF:FE99:4900 001D.7199.4900 Vl100 100 0080 7203 DOWN N/A
ND 2001:600::1 AABB.CC01.F500 Et0/0 100 0003 0 REACHABLE 3181
ND 2001:300::1 AABB.CC01.F500 Et0/0 100 0007 0 REACHABLE 9559
L 2001:400::1 001D.7199.4900 Vl100 100 0080 7188 DOWN N/A
Additional References
Related Documents
| Related Topic | Document Title |
|---|---|
|
IPv6 addressing and connectivity |
IPv6 Configuration Guide |
|
Cisco IOS commands |
|
|
IPv6 commands |
Cisco IOS IPv6 Command Reference |
|
Cisco IOS IPv6 features |
Cisco IOS IPv6 Feature Mapping |
MIBs
Technical Assistance
| Description | Link |
|---|---|
|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for IPv6 Snooping
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
| Table 1 | Feature Information for IPv6 Snooping |
| Feature Name | Releases | Feature Information |
|---|---|---|
|
IPv6 Address Glean |
15.0(2)SE |
IPv6 address glean inspects ND and DHCP messages on a link to glean addresses and then populates the binding table with these addresses. The following commands was introduced: prefix-glean. |
|
IPv6 Device Tracking |
12.2(50)SY 15.0(1)SY 15.0(2)SE |
IPv6 device tracking provides IPv6 host liveness tracking so that a neighbor table can be immediately updated when an IPv6 host disappears. The following commands were introduced or modified: ipv6 neighbor binding logging, ipv6 neighbor binding max-entries, ipv6 neighbor binding vlan, ipv6 neighbor tracking, show ipv6 neighbor binding. |
|
IPv6 Neighbor Discovery Inspection |
12.2(50)SY 15.0(1)SY 15.0(2)SE |
IPv6 neighbor discovery inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables. The following commands were introduced or modified: debug ipv6 snooping, device-role, drop-unsecure, ipv6 nd inspection, ipv6 nd inspection policy, sec-level minimum, show ipv6 snooping capture-policy, show ipv6 snooping counters, show ipv6 snooping features, show ipv6 snooping policies, tracking, trusted-port. |
|
IPv6 Snooping |
15.0(2)SE |
The IPv6 snooping feature bundles several layer 2 IPv6 first-hop security features, including IPv6 neighbor discovery, IPv6 device tracking, and IPv6 address glean. IPv6 snooping operates at layer 2, or between layer 2 and layer 3, and provides IPv6 features with security and scalability. The following commands were introduced or modified: ipv6 snooping attach-policy, ipv6 snooping policy . |
Glossary
- CA--certification authority.
- CGA--cryptographically generated address.
- CPA--certificate path answer.
- CPR--certificate path response.
- CPS--certification path solicitation. The solicitation message used in the addressing process.
- CRL--certificate revocation list.
- CS--certification server.
- CSR--certificate signing request.
- DAD--duplicate address detection. A mechanism that ensures two IPv6 nodes on the same link are not using the same address.
- DER--distinguished encoding rules. An encoding scheme for data values.
- nonce--An unpredictable random or pseudorandom number generated by a node and used once. In SeND, nonces are used to assure that a particular advertisement is linked to the solicitation that triggered it.
- non-SeND node--An IPv6 node that does not implement SeND but uses only the Neighbor Discovery protocol without security.
- NUD--neighbor unreachability detection. A mechanism used for tracking neighbor reachability.
- PACL--port-based access list.
- PKI--public key infrastructure.
- RA--router advertisement.
- RD--Router discovery allows the hosts to discover what devices exist on the link and what subnet prefixes are available. Router discovery is a part of the Neighbor Discovery protocol.
- Router Authorization Certificate--A public key certificate.
- SeND node--An IPv6 node that implements SeND.
- trust anchor--An entity that the host trusts to authorize devices to act as devices. Hosts are configured with a set of trust anchors to protect device discovery.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.