Contents

IPv6 Snooping

The IPv6 Snooping feature bundles several Layer 2 IPv6 first-hop security features, including IPv6 neighbor discovery inspection, IPv6 device tracking, IPv6 address glean, and IPv6 binding table recovery, to provide security and scalability. IPv6 ND inspection operates at Layer 2, or between Layer 2 and Layer 3, to provide IPv6 functions 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.

Restrictions for IPv6 Snooping

The IPv6 snooping feature is not supported on Etherchannel ports.

Information About IPv6 Snooping

IPv6 Global Policies

IPv6 global policies provide storage and access policy database services. IPv6 ND inspection and IPv6 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 Neighbor Discovery Inspection

The IPv6 Neighbor Discovery Inspection, or IPv6 "snooping," feature bundles several Layer 2 IPv6 first-hop security features, including IPv6 Address Glean and IPv6 Device Tracking. IPv6 neighbor discovery (ND) inspection operates at Layer 2, or between Layer 2 and Layer 3, and provides IPv6 features with security and scalability. 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 ND inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables and analyzes ND messages in order to build a trusted binding table. IPv6 ND messages that do not have valid bindings are dropped. An ND message is considered trustworthy if its IPv6-to-MAC mapping is verifiable.

When IPv6 ND inspection is configured on a target (which varies depending on platform target support and may include device ports, switch ports, Layer 2 interfaces, Layer 3 interfaces, and VLANs), capture instructions are downloaded to the hardware to redirect the 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 ND inspection 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 ND inspection entry point. This entry point is the last to be called, so any decision (such as drop) made by another feature supersedes the IPv6 ND inspection decision.

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

The IPv6 First-Hop Security Binding Table recovery mechanism feature enables the binding table to recover in the event of a device reboot. A database table of IPv6 neighbors connected to the device is created from information sources such as ND 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.

This mechanism enables the binding table to recover in the event of a device reboot. The recovery mechanism will block any data traffic sourced from an unknown source; that is, a source not already specified in the binding table and previously learned through ND or DHCP gleaning. This feature recovers the missing binding table entries when the resolution for a destination address fails in the destination guard. When a failure occurs, a binding table entry is recovered by querying the DHCP server or the destination host, depending on the configuration.

Recovery Protocols and Prefix Lists

The IPv6 First-Hop Security Binding Table Recovery Mechanism feature introduces the capability to provide a prefix list that is matched before the recovery is attempted for both DHCP and NDP.

If an address does not match the prefix list associated with the protocol, then the recovery of the binding table entry will not be attempted with that protocol. The prefix list should correspond to the prefixes that are valid for address assignment in the Layer 2 domain using the protocol. The default is that there is no prefix list, in which case the recovery is attempted for all addresses. The command to associate a prefix list to a protocol is protocol {dhcp | ndp} [prefix-list prefix-list-name].

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 Address Glean

IPv6 address glean 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.

Figure 1. IPv6 Address Glean

How to Configure IPv6 Snooping

Configuring IPv6 ND Inspection

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ipv6 snooping policy snooping-policy

    4.    ipv6 snooping attach-policy snooping-policy


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 ipv6 snooping policy snooping-policy


    Example:
    Device(config)# ipv6 snooping policy policy1
     

    Configures an IPv6 snooping policy and enters IPv6 snooping configuration mode.

     
    Step 4ipv6 snooping attach-policy snooping-policy


    Example:
    Device(config-ipv6-snooping)# ipv6 snooping attach-policy policy1
     

    Attaches the IPv6 snooping policy to a target.

     

    Configuring IPv6 ND Inspection Globally

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    ipv6 nd inspection policy policy-name

      4.    drop-unsecure

      5.    sec-level minimum value

      6.    device-role {host | monitor | router}

      7.    tracking {enable [reachable-lifetime {value | infinite}] | disable [stale-lifetime {value | infinite}]}

      8.    trusted-port


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 ipv6 nd inspection policy policy-name


      Example:
      Device(config)# ipv6 nd inspection policy policy1
       

      Defines the ND inspection policy name and enters ND inspection policy configuration mode.

       
      Step 4 drop-unsecure


      Example:
      Device(config-nd-inspection)# drop-unsecure
       

      Drops messages with no options, invalid options, or an invalid signature.

       
      Step 5 sec-level minimum value


      Example:
      Device(config-nd-inspection)# sec-level minimum 2
       

      Specifies the minimum security level parameter value when cryptographically generated address (CGA) options are used.

       
      Step 6 device-role {host | monitor | router}


      Example:
      Device(config-nd-inspection)# device-role monitor
       

      Specifies the role of the device attached to the port.

       
      Step 7 tracking {enable [reachable-lifetime {value | infinite}] | disable [stale-lifetime {value | infinite}]}


      Example:
      Device(config-nd-inspection)# tracking disable stale-lifetime infinite
       

      Overrides the default tracking policy on a port.

       
      Step 8 trusted-port


      Example:
      Device(config-nd-inspection)# trusted-port
       

      Configures a port to become a trusted port.

       

      Applying IPv6 ND Inspection on an Interface

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    interface type number

        4.    ipv6 nd inspection [attach-policy [policy policy-name] | vlan {add | except | none | remove | all} vlan [vlan1, vlan2, vlan3...]]


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.

         
        Step 2 configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3 interface type number


        Example:
        Device(config)# interface fastethernet 0/0
         

        Specifies an interface type and number and enters interface configuration mode.

         
        Step 4 ipv6 nd inspection [attach-policy [policy policy-name] | vlan {add | except | none | remove | all} vlan [vlan1, vlan2, vlan3...]]


        Example:
        Device(config-if)# ipv6 nd inspection
         

        Applies the ND Inspection feature on the interface.

         

        Verifying and Troubleshooting IPv6 ND Inspection

        SUMMARY STEPS

          1.    enable

          2.    show ipv6 snooping capture-policy [interface type number]

          3.    show ipv6 snooping counter [interface type number]

          4.    show ipv6 snooping features

          5.    show ipv6 snooping policies [interface type number]

          6.    debug ipv6 snooping


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 enable


          Example:
          Device> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.

           
          Step 2 show ipv6 snooping capture-policy [interface type number]


          Example:
          Device# show ipv6 snooping capture-policy interface ethernet 0/0
           

          Displays snooping ND message capture policies.

           
          Step 3 show ipv6 snooping counter [interface type number]


          Example:
          Device# show ipv6 snooping counter interface FastEthernet 4/12
           

          Displays information about the packets counted by the interface counter.

           
          Step 4 show ipv6 snooping features


          Example:
          Device# show ipv6 snooping features
           

          Displays information about snooping features configured on the device.

           
          Step 5 show ipv6 snooping policies [interface type number]


          Example:
          Device# show ipv6 snooping policies
           

          Displays information about the configured policies and the interfaces to which they are attached.

           
          Step 6 debug ipv6 snooping


          Example:
          Device# debug ipv6 snooping
           

          Enables debugging for snooping information in IPv6.

           

          Configuring IPv6 Device Tracking

          Configuring IPv6 First-Hop Security Binding Table Recovery

          SUMMARY STEPS

            1.    enable

            2.    configure terminal

            3.    ipv6 neighbor binding vlan vlan-id {interface type number | ipv6-address | mac-address} [tracking [disable | enable | retry-interval value] | reachable-lifetime value]

            4.    ipv6 neighbor binding max-entries entries [vlan-limit number | interface-limit number | mac-limit number]

            5.    ipv6 neighbor binding logging

            6.    exit

            7.    show ipv6 neighbor binding [vlan vlan-id | interface type number | ipv6 ipv6-address | mac mac-address]


          DETAILED STEPS
             Command or ActionPurpose
            Step 1 enable


            Example:
            Device> enable
             

            Enables privileged EXEC mode.

            • Enter your password if prompted.

             
            Step 2 configure terminal


            Example:
            Device# configure terminal
             

            Enters global configuration mode.

             
            Step 3 ipv6 neighbor binding vlan vlan-id {interface type number | ipv6-address | mac-address} [tracking [disable | enable | retry-interval value] | reachable-lifetime value]


            Example:
            Device(config)# ipv6 neighbor binding vlan 100 interface Ethernet 0/0 reachable-lifetime 100
             

            Adds a static entry to the binding table database.

             
            Step 4 ipv6 neighbor binding max-entries entries [vlan-limit number | interface-limit number | mac-limit number]


            Example:
            Device(config)# ipv6 neighbor binding max-entries 100
             

            Specifies the maximum number of entries that are allowed to be inserted in the binding table cache.

             
            Step 5 ipv6 neighbor binding logging


            Example:
            Device(config)# ipv6 neighbor binding logging
             

            Enables the logging of binding table main events.

             
            Step 6 exit


            Example:
            Device(config)# exit
             

            Exits global configuration mode and enters privileged EXEC mode.

             
            Step 7 show ipv6 neighbor binding [vlan vlan-id | interface type number | ipv6 ipv6-address | mac mac-address]


            Example:
            Device# show ipv6 neighbor binding
             

            Displays the contents of a binding table.

             

            Configuring the IPv6 First-Hop Security Binding Table Recovery Mechanism

            SUMMARY STEPS

              1.    enable

              2.    configure terminal

              3.    ipv6 neighbor binding vlan vlan-id ipv6-address interface type number

              4.    ipv6 prefix-list list-name permit ipv6-prefix/prefix-length ge ge-value

              5.    ipv6 snooping policy snooping-policy-id

              6.    destination-glean {recovery | log-only} [dhcp]

              7.    protocol dhcp [prefix-list prefix-list-name]

              8.    exit

              9.    ipv6 destination-guard policy policy-name

              10.    enforcement {always | stressed}

              11.    exit

              12.    ipv6 dhcp guard policy policy-name

              13.    device-role server

              14.    exit

              15.    vlan configuration vlan-list-id

              16.    ipv6 snooping attach-policy policy-name

              17.    ipv6 destination-guard attach-policy policy-name

              18.    end


            DETAILED STEPS
               Command or ActionPurpose
              Step 1 enable


              Example:
              Device> enable
               

              Enables privileged EXEC mode.

              • Enter your password if prompted.

               
              Step 2 configure terminal


              Example:
              Device# configure terminal
               

              Enters global configuration mode.

               
              Step 3ipv6 neighbor binding vlan vlan-id ipv6-address interface type number


              Example:
              Device(config)# ipv6 neighbor binding vlan 100 2001:db8::1 interface ethernet3/0
               

              Adds a static entry to the binding table database.

               
              Step 4ipv6 prefix-list list-name permit ipv6-prefix/prefix-length ge ge-value


              Example:
              Device(config)# ipv6 prefix-list abc permit 2001:DB8::/64 ge 128
               

              Creates an entry in an IPv6 prefix list.

               
              Step 5ipv6 snooping policy snooping-policy-id


              Example:
              Device(config)# ipv6 snooping policy xyz
               

              Enters IPv6 snooping configuration mode and allows you to modify the configuration of the snooping policy specified.

               
              Step 6destination-glean {recovery | log-only} [dhcp]


              Example:
              Device(config-ipv6-snooping)# destination-glean recovery dhcp
               

              Specifies that destination addresses should be recovered from DHCP.

              Note   

              If logging (without recovery) is required, use the destination-glean log-only command.

               
              Step 7protocol dhcp [prefix-list prefix-list-name]


              Example:
              Device(config-ipv6-snooping)# protocol dhcp prefix-list abc
               

              (Optional) Specifies that addresses should be gleaned with DHCP and associates the protocol with a specific IPv6 prefix list.

               
              Step 8exit


              Example:
              Device(config-ipv6-snooping)# exit
               

              Exits IPv6 snooping configuration mode and returns to global configuration mode.

               
              Step 9ipv6 destination-guard policy policy-name


              Example:
              Device(config)# ipv6 destination-guard policy xyz
               

              (Optional) Enters destination guard configuration mode and allows you to modify the configuration of the specified destination guard policy.

               
              Step 10enforcement {always | stressed}


              Example:
              Device(config-destguard)# enforcement stressed
               

              Sets the enforcement level of the policy to be either enforced under all conditions or only when the system is under stress.

               
              Step 11exit


              Example:
              Device(config-destguard)# exit
               

              Exits destination guard configuration mode and returns to global configuration mode.

               
              Step 12ipv6 dhcp guard policy policy-name


              Example:
              Device(config)# ipv6 dhcp guard policy server_side
               

              Enters DHCP guard configuration mode and allows you to modify the configuration of the specified DHCP guard policy.

               
              Step 13device-role server


              Example:
              Device(config-dhcp-guard)# device-role server
               

              Sets the role of the device that is attached to the server.

               
              Step 14exit


              Example:
              Device(config-destguard)# exit
               

              Exits DHCP guard configuration mode and returns to global configuration mode.

               
              Step 15vlan configuration vlan-list-id


              Example:
              Device(config)# vlan configuration 100
               

              Enters VLAN configuration mode and allows you to modify the configuration of the specified VLAN.

               
              Step 16ipv6 snooping attach-policy policy-name


              Example:
              Device(config-vlan-config)# ipv6 snooping attach-policy xyz
               

              Attaches the IPv6 snooping policy to a VLAN.

               
              Step 17ipv6 destination-guard attach-policy policy-name


              Example:
              Device(config-vlan-config)# ipv6 destination-guard attach-policy xyz
               
              Attaches the destination guard policy to the specified VLAN.
              Note   

              For information about how to configure an IPv6 destination guard policy, see the “IPv6 Destination Guard” module.

               
              Step 18end


              Example:
              Device(config-vlan-config)# end
               

              Exits VLAN configuration mode and returns to privileged EXEC mode.

               

              Configuring Address Gleaning and Associating Recovery Protocols with Prefix Lists

              SUMMARY STEPS

                1.    enable

                2.    configure terminal

                3.    ipv6 snooping policy snooping-policy-id

                4.    protocol {dhcp | ndp} [prefix-list prefix-list-name]

                5.    end


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1 enable


                Example:
                Device> enable
                 

                Enables privileged EXEC mode.

                • Enter your password if prompted.

                 
                Step 2 configure terminal


                Example:
                Device# configure terminal
                 

                Enters global configuration mode.

                 
                Step 3ipv6 snooping policy snooping-policy-id


                Example:
                Device(config)# ipv6 snooping policy 200
                 

                Enters IPv6 snooping configuration mode and allows you to modify the configuration of the snooping policy specified.

                 
                Step 4protocol {dhcp | ndp} [prefix-list prefix-list-name]


                Example:
                Device(config-ipv6-snooping)# protocol dhcp prefix-list dhcp_prefix_list
                 

                Specifies that address should be gleaned with dynamic Host Configuration Protocol (DHCP) and associates a recovery protocol (DHCP) with the prefix list.

                 
                Step 5end


                Example:
                Device(config-ipv6-snooping)# end
                 

                Exits IPv6 snooping configuration mode and returns to privileged EXEC mode.

                 

                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.

                SUMMARY STEPS

                  1.    enable

                  2.    configure terminal

                  3.    ipv6 neighbor tracking [retry-interval value]


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1 enable


                  Example:
                  Device> enable
                   

                  Enables privileged EXEC mode.

                  • Enter your password if prompted.

                   
                  Step 2 configure terminal


                  Example:
                  Device# configure terminal
                   

                  Enters global configuration mode.

                   
                  Step 3 ipv6 neighbor tracking [retry-interval value]


                  Example:
                  Device(config)# ipv6 neighbor tracking
                   

                  Tracks entries in the binding table.

                   

                  Configuring IPv6 Prefix Glean

                  SUMMARY STEPS

                    1.    enable

                    2.    configure terminal

                    3.    ipv6 snooping policy snooping-policy

                    4.    prefix-glean [only]


                  DETAILED STEPS
                     Command or ActionPurpose
                    Step 1 enable


                    Example:
                    Device> enable
                     

                    Enables privileged EXEC mode.

                    • Enter your password if prompted.

                     
                    Step 2 configure terminal


                    Example:
                    Device# configure terminal
                     

                    Enters global configuration mode.

                     
                    Step 3 ipv6 snooping policy snooping-policy


                    Example:
                    Device(config)# ipv6 snooping policy policy1
                     

                    Configures an IPv6 snooping policy and enters IPv6 snooping policy configuration mode.

                     
                    Step 4prefix-glean [only]


                    Example:
                    Device(config-ipv6-snooping)# prefix-glean
                     

                    Enables the device to glean prefixes from IPv6 RAs or DHCPv6 traffic.

                     

                    Configuration Examples for IPv6 Snooping

                    Example: Configuring IPv6 ND Inspection

                    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: Configuring IPv6 ND Inspection and RA Guard

                    This example provides information about an interface on which both the Neighbor Discovery Inspection and 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: Configuring IPv6 Binding Table Content

                    ipv6 neighbor binding vlan 100 ethernet 0/0 reachable-entries 100
 ipv6 neighbor binding max-entries 100
 ipv6 neighbor binding logging
 exit

                    Example: Configuring IPv6 First-Hop Security Binding Table Recovery

                    ipv6 dhcp-client leasequery server 2001:db8::1 vlan 100
ipv6 neighbor binding vlan 100 2001:db8::1 interface ethernet3/0

ipv6 prefix-list abc permit 2001:DB8::/64 ge 128
ipv6 snooping policy xyz
destination-glean recovery dhcp 
protocol dhcp prefix-list abc
 ipv6 destination-guard policy xyz
 exit

ipv6 dhcp guard policy server_side
 device-role server

vlan configuration 100
 ipv6 snooping attach-policy xyz
 ipv6 destination-guard attach-policy xyz

interface ethernet3/0
 switchport
 switchport access vlan 100
 switchport mode access
 duplex auto
 ipv6 dhcp guard attach-policy server_side

interface vlan100
 no ip address
 ipv6 address 2001:DB8::100/64

                    Example: Configuring Address Gleaning and Associating Recovery Protocols with Prefix Lists

                    The following example shows that NDP will be used for the recovery for all addresses and that DHCP will be used to recover addresses that match the prefix list called dhcp_prefix_list: 

                    Device(config-ipv6-snooping)# protocol ndp 
Device(config-ipv6-snooping)# protocol dhcp prefix-list dhcp_prefix_list

                    Example: Verifying IPv6 Device Tracking

                    Device# show ipv6 neighbor

    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 for IPv6 Source Guard and Prefix Guard

                    Related Documents

                    Related Topic

                    Document Title

                    IPv6 addressing and connectivity

                    IPv6 Configuration Guide

                    IPv4 addressing

                    IP Addressing: IPv4 Addressing Configuration Guide

                    Cisco IOS commands

                    Cisco IOS Master Command List, All Releases

                    IPv6 commands

                    Cisco IOS IPv6 Command Reference

                    Cisco IOS IPv6 features

                    Cisco IOS IPv6 Feature Mapping

                    Standards and RFCs

                    Standard/RFC

                    Title

                    RFCs for IPv6

                    IPv6 RFCs

                    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.

                    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

                    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 Snooping

                    12.2(50)SY

                    15.0(1)SY

                    15.0(2)SE

                    15.1(2)SG

                    15.3(1)S

                    Cisco IOS XE Release 3.2SE

                    Cisco IOS XE Release 3.8S

                    Cisco IOS Release 15.2(1)E

                    IPv6 snooping bundles several Layer 2 IPv6 first-hop security features, including IPv6 ND inspection, IPv6 device tracking, IPv6 address glean, and IPv6 first-hop security binding table recovery, to provide security and scalability. IPv6 snooping operates at Layer 2, or between Layer 2 and Layer 3, to provide IPv6 functions with security and scalability.

                    The following commands were introduced or modified: data-glean, debug ipv6 snooping, destination-glean, device-role, drop-unsecure, ipv6 nd inspection, ipv6 nd inspection policy, ipv6 neighbor binding logging, ipv6 neighbor binding max-entries, ipv6 neighbor binding vlan, ipv6 neighbor tracking, ipv6 snooping attach-policy, ipv6 snooping policy, prefix-glean, protocol (IPv6), sec-level minimum, show ipv6 neighbor binding, show ipv6 snooping capture-policy, show ipv6 snooping counters, show ipv6 snooping features, show ipv6 snooping policies, tracking, trusted-port.

                    IPv6 Snooping

                    Contents

                    IPv6 Snooping

                    The IPv6 Snooping feature bundles several Layer 2 IPv6 first-hop security features, including IPv6 neighbor discovery inspection, IPv6 device tracking, IPv6 address glean, and IPv6 binding table recovery, to provide security and scalability. IPv6 ND inspection operates at Layer 2, or between Layer 2 and Layer 3, to provide IPv6 functions 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.

                    Restrictions for IPv6 Snooping

                    The IPv6 snooping feature is not supported on Etherchannel ports.

                    Information About IPv6 Snooping

                    IPv6 Global Policies

                    IPv6 global policies provide storage and access policy database services. IPv6 ND inspection and IPv6 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 Neighbor Discovery Inspection

                    The IPv6 Neighbor Discovery Inspection, or IPv6 "snooping," feature bundles several Layer 2 IPv6 first-hop security features, including IPv6 Address Glean and IPv6 Device Tracking. IPv6 neighbor discovery (ND) inspection operates at Layer 2, or between Layer 2 and Layer 3, and provides IPv6 features with security and scalability. 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 ND inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables and analyzes ND messages in order to build a trusted binding table. IPv6 ND messages that do not have valid bindings are dropped. An ND message is considered trustworthy if its IPv6-to-MAC mapping is verifiable.

                    When IPv6 ND inspection is configured on a target (which varies depending on platform target support and may include device ports, switch ports, Layer 2 interfaces, Layer 3 interfaces, and VLANs), capture instructions are downloaded to the hardware to redirect the 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 ND inspection 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 ND inspection entry point. This entry point is the last to be called, so any decision (such as drop) made by another feature supersedes the IPv6 ND inspection decision.

                    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

                    The IPv6 First-Hop Security Binding Table recovery mechanism feature enables the binding table to recover in the event of a device reboot. A database table of IPv6 neighbors connected to the device is created from information sources such as ND 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.

                    This mechanism enables the binding table to recover in the event of a device reboot. The recovery mechanism will block any data traffic sourced from an unknown source; that is, a source not already specified in the binding table and previously learned through ND or DHCP gleaning. This feature recovers the missing binding table entries when the resolution for a destination address fails in the destination guard. When a failure occurs, a binding table entry is recovered by querying the DHCP server or the destination host, depending on the configuration.

                    Recovery Protocols and Prefix Lists

                    The IPv6 First-Hop Security Binding Table Recovery Mechanism feature introduces the capability to provide a prefix list that is matched before the recovery is attempted for both DHCP and NDP.

                    If an address does not match the prefix list associated with the protocol, then the recovery of the binding table entry will not be attempted with that protocol. The prefix list should correspond to the prefixes that are valid for address assignment in the Layer 2 domain using the protocol. The default is that there is no prefix list, in which case the recovery is attempted for all addresses. The command to associate a prefix list to a protocol is protocol {dhcp | ndp} [prefix-list prefix-list-name].

                    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 Address Glean

                    IPv6 address glean 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.

                    Figure 1. IPv6 Address Glean

                    How to Configure IPv6 Snooping

                    Configuring IPv6 ND Inspection

                    SUMMARY STEPS

                      1.    enable

                      2.    configure terminal

                      3.    ipv6 snooping policy snooping-policy

                      4.    ipv6 snooping attach-policy snooping-policy


                    DETAILED STEPS
                       Command or ActionPurpose
                      Step 1 enable


                      Example:
                      Device> enable
                       

                      Enables privileged EXEC mode.

                      • Enter your password if prompted.

                       
                      Step 2 configure terminal


                      Example:
                      Device# configure terminal
                       

                      Enters global configuration mode.

                       
                      Step 3 ipv6 snooping policy snooping-policy


                      Example:
                      Device(config)# ipv6 snooping policy policy1
                       

                      Configures an IPv6 snooping policy and enters IPv6 snooping configuration mode.

                       
                      Step 4ipv6 snooping attach-policy snooping-policy


                      Example:
                      Device(config-ipv6-snooping)# ipv6 snooping attach-policy policy1
                       

                      Attaches the IPv6 snooping policy to a target.

                       

                      Configuring IPv6 ND Inspection Globally

                      SUMMARY STEPS

                        1.    enable

                        2.    configure terminal

                        3.    ipv6 nd inspection policy policy-name

                        4.    drop-unsecure

                        5.    sec-level minimum value

                        6.    device-role {host | monitor | router}

                        7.    tracking {enable [reachable-lifetime {value | infinite}] | disable [stale-lifetime {value | infinite}]}

                        8.    trusted-port


                      DETAILED STEPS
                         Command or ActionPurpose
                        Step 1 enable


                        Example:
                        Device> enable
                         

                        Enables privileged EXEC mode.

                        • Enter your password if prompted.

                         
                        Step 2 configure terminal


                        Example:
                        Device# configure terminal
                         

                        Enters global configuration mode.

                         
                        Step 3 ipv6 nd inspection policy policy-name


                        Example:
                        Device(config)# ipv6 nd inspection policy policy1
                         

                        Defines the ND inspection policy name and enters ND inspection policy configuration mode.

                         
                        Step 4 drop-unsecure


                        Example:
                        Device(config-nd-inspection)# drop-unsecure
                         

                        Drops messages with no options, invalid options, or an invalid signature.

                         
                        Step 5 sec-level minimum value


                        Example:
                        Device(config-nd-inspection)# sec-level minimum 2
                         

                        Specifies the minimum security level parameter value when cryptographically generated address (CGA) options are used.

                         
                        Step 6 device-role {host | monitor | router}


                        Example:
                        Device(config-nd-inspection)# device-role monitor
                         

                        Specifies the role of the device attached to the port.

                         
                        Step 7 tracking {enable [reachable-lifetime {value | infinite}] | disable [stale-lifetime {value | infinite}]}


                        Example:
                        Device(config-nd-inspection)# tracking disable stale-lifetime infinite
                         

                        Overrides the default tracking policy on a port.

                         
                        Step 8 trusted-port


                        Example:
                        Device(config-nd-inspection)# trusted-port
                         

                        Configures a port to become a trusted port.

                         

                        Applying IPv6 ND Inspection on an Interface

                        SUMMARY STEPS

                          1.    enable

                          2.    configure terminal

                          3.    interface type number

                          4.    ipv6 nd inspection [attach-policy [policy policy-name] | vlan {add | except | none | remove | all} vlan [vlan1, vlan2, vlan3...]]


                        DETAILED STEPS
                           Command or ActionPurpose
                          Step 1 enable


                          Example:
                          Device> enable
                           

                          Enables privileged EXEC mode.

                          • Enter your password if prompted.

                           
                          Step 2 configure terminal


                          Example:
                          Device# configure terminal
                           

                          Enters global configuration mode.

                           
                          Step 3 interface type number


                          Example:
                          Device(config)# interface fastethernet 0/0
                           

                          Specifies an interface type and number and enters interface configuration mode.

                           
                          Step 4 ipv6 nd inspection [attach-policy [policy policy-name] | vlan {add | except | none | remove | all} vlan [vlan1, vlan2, vlan3...]]


                          Example:
                          Device(config-if)# ipv6 nd inspection
                           

                          Applies the ND Inspection feature on the interface.

                           

                          Verifying and Troubleshooting IPv6 ND Inspection

                          SUMMARY STEPS

                            1.    enable

                            2.    show ipv6 snooping capture-policy [interface type number]

                            3.    show ipv6 snooping counter [interface type number]

                            4.    show ipv6 snooping features

                            5.    show ipv6 snooping policies [interface type number]

                            6.    debug ipv6 snooping


                          DETAILED STEPS
                             Command or ActionPurpose
                            Step 1 enable


                            Example:
                            Device> enable
                             

                            Enables privileged EXEC mode.

                            • Enter your password if prompted.

                             
                            Step 2 show ipv6 snooping capture-policy [interface type number]


                            Example:
                            Device# show ipv6 snooping capture-policy interface ethernet 0/0
                             

                            Displays snooping ND message capture policies.

                             
                            Step 3 show ipv6 snooping counter [interface type number]


                            Example:
                            Device# show ipv6 snooping counter interface FastEthernet 4/12
                             

                            Displays information about the packets counted by the interface counter.

                             
                            Step 4 show ipv6 snooping features


                            Example:
                            Device# show ipv6 snooping features
                             

                            Displays information about snooping features configured on the device.

                             
                            Step 5 show ipv6 snooping policies [interface type number]


                            Example:
                            Device# show ipv6 snooping policies
                             

                            Displays information about the configured policies and the interfaces to which they are attached.

                             
                            Step 6 debug ipv6 snooping


                            Example:
                            Device# debug ipv6 snooping
                             

                            Enables debugging for snooping information in IPv6.

                             

                            Configuring IPv6 Device Tracking

                            Configuring IPv6 First-Hop Security Binding Table Recovery

                            SUMMARY STEPS

                              1.    enable

                              2.    configure terminal

                              3.    ipv6 neighbor binding vlan vlan-id {interface type number | ipv6-address | mac-address} [tracking [disable | enable | retry-interval value] | reachable-lifetime value]

                              4.    ipv6 neighbor binding max-entries entries [vlan-limit number | interface-limit number | mac-limit number]

                              5.    ipv6 neighbor binding logging

                              6.    exit

                              7.    show ipv6 neighbor binding [vlan vlan-id | interface type number | ipv6 ipv6-address | mac mac-address]


                            DETAILED STEPS
                               Command or ActionPurpose
                              Step 1 enable


                              Example:
                              Device> enable
                               

                              Enables privileged EXEC mode.

                              • Enter your password if prompted.

                               
                              Step 2 configure terminal


                              Example:
                              Device# configure terminal
                               

                              Enters global configuration mode.

                               
                              Step 3 ipv6 neighbor binding vlan vlan-id {interface type number | ipv6-address | mac-address} [tracking [disable | enable | retry-interval value] | reachable-lifetime value]


                              Example:
                              Device(config)# ipv6 neighbor binding vlan 100 interface Ethernet 0/0 reachable-lifetime 100
                               

                              Adds a static entry to the binding table database.

                               
                              Step 4 ipv6 neighbor binding max-entries entries [vlan-limit number | interface-limit number | mac-limit number]


                              Example:
                              Device(config)# ipv6 neighbor binding max-entries 100
                               

                              Specifies the maximum number of entries that are allowed to be inserted in the binding table cache.

                               
                              Step 5 ipv6 neighbor binding logging


                              Example:
                              Device(config)# ipv6 neighbor binding logging
                               

                              Enables the logging of binding table main events.

                               
                              Step 6 exit


                              Example:
                              Device(config)# exit
                               

                              Exits global configuration mode and enters privileged EXEC mode.

                               
                              Step 7 show ipv6 neighbor binding [vlan vlan-id | interface type number | ipv6 ipv6-address | mac mac-address]


                              Example:
                              Device# show ipv6 neighbor binding
                               

                              Displays the contents of a binding table.

                               

                              Configuring the IPv6 First-Hop Security Binding Table Recovery Mechanism

                              SUMMARY STEPS

                                1.    enable

                                2.    configure terminal

                                3.    ipv6 neighbor binding vlan vlan-id ipv6-address interface type number

                                4.    ipv6 prefix-list list-name permit ipv6-prefix/prefix-length ge ge-value

                                5.    ipv6 snooping policy snooping-policy-id

                                6.    destination-glean {recovery | log-only} [dhcp]

                                7.    protocol dhcp [prefix-list prefix-list-name]

                                8.    exit

                                9.    ipv6 destination-guard policy policy-name

                                10.    enforcement {always | stressed}

                                11.    exit

                                12.    ipv6 dhcp guard policy policy-name

                                13.    device-role server

                                14.    exit

                                15.    vlan configuration vlan-list-id

                                16.    ipv6 snooping attach-policy policy-name

                                17.    ipv6 destination-guard attach-policy policy-name

                                18.    end


                              DETAILED STEPS
                                 Command or ActionPurpose
                                Step 1 enable


                                Example:
                                Device> enable
                                 

                                Enables privileged EXEC mode.

                                • Enter your password if prompted.

                                 
                                Step 2 configure terminal


                                Example:
                                Device# configure terminal
                                 

                                Enters global configuration mode.

                                 
                                Step 3ipv6 neighbor binding vlan vlan-id ipv6-address interface type number


                                Example:
                                Device(config)# ipv6 neighbor binding vlan 100 2001:db8::1 interface ethernet3/0
                                 

                                Adds a static entry to the binding table database.

                                 
                                Step 4ipv6 prefix-list list-name permit ipv6-prefix/prefix-length ge ge-value


                                Example:
                                Device(config)# ipv6 prefix-list abc permit 2001:DB8::/64 ge 128
                                 

                                Creates an entry in an IPv6 prefix list.

                                 
                                Step 5ipv6 snooping policy snooping-policy-id


                                Example:
                                Device(config)# ipv6 snooping policy xyz
                                 

                                Enters IPv6 snooping configuration mode and allows you to modify the configuration of the snooping policy specified.

                                 
                                Step 6destination-glean {recovery | log-only} [dhcp]


                                Example:
                                Device(config-ipv6-snooping)# destination-glean recovery dhcp
                                 

                                Specifies that destination addresses should be recovered from DHCP.

                                Note   

                                If logging (without recovery) is required, use the destination-glean log-only command.

                                 
                                Step 7protocol dhcp [prefix-list prefix-list-name]


                                Example:
                                Device(config-ipv6-snooping)# protocol dhcp prefix-list abc
                                 

                                (Optional) Specifies that addresses should be gleaned with DHCP and associates the protocol with a specific IPv6 prefix list.

                                 
                                Step 8exit


                                Example:
                                Device(config-ipv6-snooping)# exit
                                 

                                Exits IPv6 snooping configuration mode and returns to global configuration mode.

                                 
                                Step 9ipv6 destination-guard policy policy-name


                                Example:
                                Device(config)# ipv6 destination-guard policy xyz
                                 

                                (Optional) Enters destination guard configuration mode and allows you to modify the configuration of the specified destination guard policy.

                                 
                                Step 10enforcement {always | stressed}


                                Example:
                                Device(config-destguard)# enforcement stressed
                                 

                                Sets the enforcement level of the policy to be either enforced under all conditions or only when the system is under stress.

                                 
                                Step 11exit


                                Example:
                                Device(config-destguard)# exit
                                 

                                Exits destination guard configuration mode and returns to global configuration mode.

                                 
                                Step 12ipv6 dhcp guard policy policy-name


                                Example:
                                Device(config)# ipv6 dhcp guard policy server_side
                                 

                                Enters DHCP guard configuration mode and allows you to modify the configuration of the specified DHCP guard policy.

                                 
                                Step 13device-role server


                                Example:
                                Device(config-dhcp-guard)# device-role server
                                 

                                Sets the role of the device that is attached to the server.

                                 
                                Step 14exit


                                Example:
                                Device(config-destguard)# exit
                                 

                                Exits DHCP guard configuration mode and returns to global configuration mode.

                                 
                                Step 15vlan configuration vlan-list-id


                                Example:
                                Device(config)# vlan configuration 100
                                 

                                Enters VLAN configuration mode and allows you to modify the configuration of the specified VLAN.

                                 
                                Step 16ipv6 snooping attach-policy policy-name


                                Example:
                                Device(config-vlan-config)# ipv6 snooping attach-policy xyz
                                 

                                Attaches the IPv6 snooping policy to a VLAN.

                                 
                                Step 17ipv6 destination-guard attach-policy policy-name


                                Example:
                                Device(config-vlan-config)# ipv6 destination-guard attach-policy xyz
                                 
                                Attaches the destination guard policy to the specified VLAN.
                                Note   

                                For information about how to configure an IPv6 destination guard policy, see the “IPv6 Destination Guard” module.

                                 
                                Step 18end


                                Example:
                                Device(config-vlan-config)# end
                                 

                                Exits VLAN configuration mode and returns to privileged EXEC mode.

                                 

                                Configuring Address Gleaning and Associating Recovery Protocols with Prefix Lists

                                SUMMARY STEPS

                                  1.    enable

                                  2.    configure terminal

                                  3.    ipv6 snooping policy snooping-policy-id

                                  4.    protocol {dhcp | ndp} [prefix-list prefix-list-name]

                                  5.    end


                                DETAILED STEPS
                                   Command or ActionPurpose
                                  Step 1 enable


                                  Example:
                                  Device> enable
                                   

                                  Enables privileged EXEC mode.

                                  • Enter your password if prompted.

                                   
                                  Step 2 configure terminal


                                  Example:
                                  Device# configure terminal
                                   

                                  Enters global configuration mode.

                                   
                                  Step 3ipv6 snooping policy snooping-policy-id


                                  Example:
                                  Device(config)# ipv6 snooping policy 200
                                   

                                  Enters IPv6 snooping configuration mode and allows you to modify the configuration of the snooping policy specified.

                                   
                                  Step 4protocol {dhcp | ndp} [prefix-list prefix-list-name]


                                  Example:
                                  Device(config-ipv6-snooping)# protocol dhcp prefix-list dhcp_prefix_list
                                   

                                  Specifies that address should be gleaned with dynamic Host Configuration Protocol (DHCP) and associates a recovery protocol (DHCP) with the prefix list.

                                   
                                  Step 5end


                                  Example:
                                  Device(config-ipv6-snooping)# end
                                   

                                  Exits IPv6 snooping configuration mode and returns to privileged EXEC mode.

                                   

                                  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.

                                  SUMMARY STEPS

                                    1.    enable

                                    2.    configure terminal

                                    3.    ipv6 neighbor tracking [retry-interval value]


                                  DETAILED STEPS
                                     Command or ActionPurpose
                                    Step 1 enable


                                    Example:
                                    Device> enable
                                     

                                    Enables privileged EXEC mode.

                                    • Enter your password if prompted.

                                     
                                    Step 2 configure terminal


                                    Example:
                                    Device# configure terminal
                                     

                                    Enters global configuration mode.

                                     
                                    Step 3 ipv6 neighbor tracking [retry-interval value]


                                    Example:
                                    Device(config)# ipv6 neighbor tracking
                                     

                                    Tracks entries in the binding table.

                                     

                                    Configuring IPv6 Prefix Glean

                                    SUMMARY STEPS

                                      1.    enable

                                      2.    configure terminal

                                      3.    ipv6 snooping policy snooping-policy

                                      4.    prefix-glean [only]


                                    DETAILED STEPS
                                       Command or ActionPurpose
                                      Step 1 enable


                                      Example:
                                      Device> enable
                                       

                                      Enables privileged EXEC mode.

                                      • Enter your password if prompted.

                                       
                                      Step 2 configure terminal


                                      Example:
                                      Device# configure terminal
                                       

                                      Enters global configuration mode.

                                       
                                      Step 3 ipv6 snooping policy snooping-policy


                                      Example:
                                      Device(config)# ipv6 snooping policy policy1
                                       

                                      Configures an IPv6 snooping policy and enters IPv6 snooping policy configuration mode.

                                       
                                      Step 4prefix-glean [only]


                                      Example:
                                      Device(config-ipv6-snooping)# prefix-glean
                                       

                                      Enables the device to glean prefixes from IPv6 RAs or DHCPv6 traffic.

                                       

                                      Configuration Examples for IPv6 Snooping

                                      Example: Configuring IPv6 ND Inspection

                                      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: Configuring IPv6 ND Inspection and RA Guard

                                      This example provides information about an interface on which both the Neighbor Discovery Inspection and 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: Configuring IPv6 Binding Table Content

                                      ipv6 neighbor binding vlan 100 ethernet 0/0 reachable-entries 100
 ipv6 neighbor binding max-entries 100
 ipv6 neighbor binding logging
 exit

                                      Example: Configuring IPv6 First-Hop Security Binding Table Recovery

                                      ipv6 dhcp-client leasequery server 2001:db8::1 vlan 100
ipv6 neighbor binding vlan 100 2001:db8::1 interface ethernet3/0

ipv6 prefix-list abc permit 2001:DB8::/64 ge 128
ipv6 snooping policy xyz
destination-glean recovery dhcp 
protocol dhcp prefix-list abc
 ipv6 destination-guard policy xyz
 exit

ipv6 dhcp guard policy server_side
 device-role server

vlan configuration 100
 ipv6 snooping attach-policy xyz
 ipv6 destination-guard attach-policy xyz

interface ethernet3/0
 switchport
 switchport access vlan 100
 switchport mode access
 duplex auto
 ipv6 dhcp guard attach-policy server_side

interface vlan100
 no ip address
 ipv6 address 2001:DB8::100/64

                                      Example: Configuring Address Gleaning and Associating Recovery Protocols with Prefix Lists

                                      The following example shows that NDP will be used for the recovery for all addresses and that DHCP will be used to recover addresses that match the prefix list called dhcp_prefix_list: 

                                      Device(config-ipv6-snooping)# protocol ndp 
Device(config-ipv6-snooping)# protocol dhcp prefix-list dhcp_prefix_list

                                      Example: Verifying IPv6 Device Tracking

                                      Device# show ipv6 neighbor

    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 for IPv6 Source Guard and Prefix Guard

                                      Related Documents

                                      Related Topic

                                      Document Title

                                      IPv6 addressing and connectivity

                                      IPv6 Configuration Guide

                                      IPv4 addressing

                                      IP Addressing: IPv4 Addressing Configuration Guide

                                      Cisco IOS commands

                                      Cisco IOS Master Command List, All Releases

                                      IPv6 commands

                                      Cisco IOS IPv6 Command Reference

                                      Cisco IOS IPv6 features

                                      Cisco IOS IPv6 Feature Mapping

                                      Standards and RFCs

                                      Standard/RFC

                                      Title

                                      RFCs for IPv6

                                      IPv6 RFCs

                                      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.

                                      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

                                      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 Snooping

                                      12.2(50)SY

                                      15.0(1)SY

                                      15.0(2)SE

                                      15.1(2)SG

                                      15.3(1)S

                                      Cisco IOS XE Release 3.2SE

                                      Cisco IOS XE Release 3.8S

                                      Cisco IOS Release 15.2(1)E

                                      IPv6 snooping bundles several Layer 2 IPv6 first-hop security features, including IPv6 ND inspection, IPv6 device tracking, IPv6 address glean, and IPv6 first-hop security binding table recovery, to provide security and scalability. IPv6 snooping operates at Layer 2, or between Layer 2 and Layer 3, to provide IPv6 functions with security and scalability.

                                      The following commands were introduced or modified: data-glean, debug ipv6 snooping, destination-glean, device-role, drop-unsecure, ipv6 nd inspection, ipv6 nd inspection policy, ipv6 neighbor binding logging, ipv6 neighbor binding max-entries, ipv6 neighbor binding vlan, ipv6 neighbor tracking, ipv6 snooping attach-policy, ipv6 snooping policy, prefix-glean, protocol (IPv6), sec-level minimum, show ipv6 neighbor binding, show ipv6 snooping capture-policy, show ipv6 snooping counters, show ipv6 snooping features, show ipv6 snooping policies, tracking, trusted-port.