IPv6 First-Hop Security Configuration Guide, Cisco IOS XE Release 3S
IPv6 RA Guard
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IPv6 RA Guard

The IPv6 RA Guard feature provides support for allowing the network administrator to block or reject unwanted or rogue router advertisement (RA) guard messages that arrive at the network device platform.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 document.

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 RA Guard

  • The IPv6 RA Guard feature does not offer protection in environments where IPv6 traffic is tunneled.
  • This feature is supported only in hardware when the ternary content addressable memory (TCAM) is programmed.
  • This feature can be configured on a switch port interface in the ingress direction.
  • This feature supports host mode and router mode.
  • This feature is supported only in the ingress direction; it is not supported in the egress direction.
  • This feature is supported on EtherChannel, but not on EtherChannel port members.
  • This feature is not supported on trunk ports with merge mode.
  • This feature is supported on auxiliary VLANs and private VLANs (PVLANs). In the case of PVLANs, primary VLAN features are inherited and merged with port features.
  • Packets dropped by the IPv6 RA Guard feature can be spanned.
  • If the platform ipv6 acl icmp optimize neighbor-discovery command is configured, the IPv6 RA Guard feature cannot be configured and an error message will be displayed. This command adds default global Internet Control Message Protocol (ICMP) entries that will override the RA guard ICMP entries.

Information About IPv6 RA Guard

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 RA Guard

The IPv6 RA Guard feature provides support for allowing the network administrator to block or reject unwanted or rogue RA guard messages that arrive at the network device platform. RAs are used by devices to announce themselves on the link. The IPv6 RA Guard feature analyzes these RAs and filters out RAs that are sent by unauthorized devices. In host mode, all RA and router redirect messages are disallowed on the port. The RA guard feature compares configuration information on the Layer 2 (L2) device with the information found in the received RA frame. Once the L2 device has validated the content of the RA frame and router redirect frame against the configuration, it forwards the RA to its unicast or multicast destination. If the RA frame content is not validated, the RA is dropped.

How to Configure IPv6 RA Guard

Configuring the IPv6 RA Guard Policy on the Device

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ipv6 nd raguard policy policy-name

    4.    device-role {host | router}

    5.    hop-limit {maximum | minimum limit}

    6.    managed-config-flag {on | off}

    7.    match ipv6 access-list ipv6-access-list-name

    8.    match ra prefix-list ipv6-prefix-list-name

    9.    other-config-flag {on | off}

    10.    router-preference maximum {high | low | medium}

    11.    trusted-port

    12.    exit


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 raguard policy policy-name


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

    Defines the RA guard policy name and enters RA guard policy configuration mode.

     
    Step 4 device-role {host | router}


    Example:
    Device(config-ra-guard)# device-role router
     

    Specifies the role of the device attached to the port.

     
    Step 5 hop-limit {maximum | minimum limit}


    Example:
    Device(config-ra-guard)# hop-limit minimum 3
     
    (Optional) Enables verification of the advertised hop count limit.
    • If not configured, this check will be bypassed.
     
    Step 6managed-config-flag {on | off}


    Example:
    Device(config-ra-guard)# managed-config-flag on
     
    (Optional) Enables verification that the advertised managed address configuration flag is on.
    • If not configured, this check will be bypassed.
     
    Step 7 match ipv6 access-list ipv6-access-list-name


    Example:
    Device(config-ra-guard)# match ipv6 access-list list1
     

    (Optional) Enables verification of the sender's IPv6 address in inspected messages from the configured authorized device source access list.

    • If not configured, this check will be bypassed.
     
    Step 8 match ra prefix-list ipv6-prefix-list-name


    Example:
    Device(config-ra-guard)# match ra prefix-list listname1
     

    (Optional) Enables verification of the advertised prefixes in inspected messages from the configured authorized prefix list.

    • If not configured, this check will be bypassed.
     
    Step 9other-config-flag {on | off}


    Example:
    Device(config-ra-guard)# other-config-flag on
     

    (Optional) Enables verification of the advertised “other” configuration parameter.

     
    Step 10 router-preference maximum {high | low | medium}


    Example:
    Device(config-ra-guard)# router-preference maximum high
     

    (Optional) Enables verification that the advertised default router preference parameter value is lower than or equal to a specified limit.

     
    Step 11trusted-port


    Example:
    Device(config-ra-guard)# trusted-port
     
    (Optional) Specifies that this policy is being applied to trusted ports.
    • All RA guard policing will be disabled.
     
    Step 12exit


    Example:
    Device(config-ra-guard)# exit
     

    Exits RA guard policy configuration mode and returns to global configuration mode.

     

    Configuring IPv6 RA Guard on an Interface

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type number

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

      5.    exit

      6.    show ipv6 nd raguard policy [policy-name]

      7.    debug ipv6 snooping raguard [filter | interface | vlanid]


    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 3/13
       

      Specifies an interface type and number, and places the device in interface configuration mode.

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


      Example:
      Device(config-if)# ipv6 nd raguard attach-policy
       

      Applies the IPv6 RA Guard feature to a specified interface.

       
      Step 5exit


      Example:
      Device(config-if)# exit
       

      Exits interface configuration mode.

       
      Step 6 show ipv6 nd raguard policy [policy-name]


      Example:
      Device# show ipv6 nd raguard policy raguard1
       

      Displays the RA guard policy on all interfaces configured with the RA guard.

       
      Step 7 debug ipv6 snooping raguard [filter | interface | vlanid]


      Example:
      Device# debug ipv6 snooping raguard
       

      Enables debugging for IPv6 RA guard snooping information.

       

      Configuration Examples for IPv6 RA Guard

      Example: IPv6 RA Guard Configuration

      Device(config)# interface fastethernet 3/13
      Device(config-if)# ipv6 nd raguard attach-policy 
      Device# show running-config interface fastethernet 3/13
 
Building configuration... 
Current configuration : 129 bytes 
! 
interface FastEthernet3/13 
 switchport 
 switchport access vlan 222 
 switchport mode access 
 access-group mode prefer port 
 ipv6 nd raguard 
end

      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

      Additional References

      Related Documents

      Related Topic

      Document Title

      IPv6 addressing and connectivity

      IPv6 Configuration Guide

      Cisco IOS commands

      Cisco IOS Master Commands 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

      MIBs

      MIB

      MIBs Link

      No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

      To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

      http:/​/​www.cisco.com/​go/​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.

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

      Feature Information for IPv6 RA Guard

      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 RA Guard

      Feature Name

      Releases

      Feature Information

      IPv6 RA Guard

      12.2(33)SXI4

      12.2(50)SY

      12.2(54)SG

      15.0(2)SE

      15.0(2)SG

      15.2(4)S

      15.2(4)M

      Cisco IOS XE Release 3.8S

      Cisco IOS XE Release 3.2SE

      Cisco IOS XE Release 3.2SG

      The IPv6 RA Guard feature provides support for allowing the network administrator to block or reject unwanted or rogue RA guard messages that arrive at the network device platform.

      The following commands were introduced or modified: debug ipv6 snooping raguard, device-role, hop-limit, ipv6 nd raguard attach-policy, ipv6 nd raguard policy, managed-config-flag, match ipv6 access-list, match ra prefix-list, other-config-flag, router-preference maximum, show ipv6 nd raguard policy.