IPv6 Services—Standard Access Control Lists

Access lists determine the type of traffic that is blocked or forwarded at device interfaces. Access control lists (ACLs) allow the filtering of inbound and outbound traffic at interfaces based on source and destination addresses.

This module provides information about standard IPv6 ACLs.

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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.

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Information About IPv6 Services--Standard Access Control Lists

Access Control Lists for IPv6 Traffic Filtering

The standard ACL functionality in IPv6 is similar to standard ACLs in IPv4. Access lists determine what traffic is blocked and what traffic is forwarded at device interfaces and allow filtering based on source and destination addresses, inbound and outbound to a specific interface. Each access list has an implicit deny statement at the end. IPv6 ACLs are defined and their deny and permit conditions are set using the ipv6 access-listcommand with the deny and permit keywords in global configuration mode.

IPv6 extended ACLs augments standard IPv6 ACL functionality to support traffic filtering based on IPv6 option headers and optional, upper-layer protocol type information for finer granularity of control (functionality similar to extended ACLs in IPv4).

IPv6 Packet Inspection

The following header fields are used for IPv6 inspection: traffic class, flow label, payload length, next header, hop limit, and source or destination IP address. For further information on and descriptions of the IPv6 header fields, see RFC 2474.

Access Class Filtering in IPv6

Filtering incoming and outgoing connections to and from the device based on an IPv6 ACL is performed using the ipv6 access-class command in line configuration mode. The ipv6 access-class command is similar to the access-class command, except the IPv6 ACLs are defined by a name. If the IPv6 ACL is applied to inbound traffic, the source address in the ACL is matched against the incoming connection source address and the destination address in the ACL is matched against the local device address on the interface. If the IPv6 ACL is applied to outbound traffic, the source address in the ACL is matched against the local device address on the interface and the destination address in the ACL is matched against the outgoing connection source address. We recommend that identical restrictions are set on all the virtual terminal lines because a user can attempt to connect to any of them.

How to Configure IPv6 Services--Standard Access Control Lists

Configuring IPv6 Services—Standard Access Control Lists

IPv6 access control lists (ACLs) do not contain implicit permit rules.

The IPv6 neighbor discovery process uses the IPv6 network-layer service; therefore, you must configure IPv6 ACLs to allow IPv6 neighbor discovery packets to be sent and received on an interface.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ipv6 access-list access-list-name

    4.    permit source-ipv6-prefix/prefix-length host

    5.    deny protocol source-ipv6-prefix/prefix-length eq telnet any

    6.    exit

    7.    interface type number

    8.    ipv6 traffic-filter access-list-name {in | out}

    9.    end

    10.    show ipv6 access-list [access-list-name]


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 access-list access-list-name


    Example: 
    Device(config)# ipv6 access-list ipv6acl
     
    Defines an IPv6 ACL and enters IPv6 access list configuration mode.

    • IPv6 ACL names cannot contain a space or quotation mark or begin with a numeral.

     
    Step 4 permit source-ipv6-prefix/prefix-length host


    Example: 
    Device(config-ipv6-acl)# permit 2001:DB8:1::1/32 any
     

    Specifies permit conditions for the IPv6 access list.

     
    Step 5 deny protocol source-ipv6-prefix/prefix-length eq telnet any


    Example: 
    Device(config-ipv6-acl)# deny tcp 2001:DB8:0300:0201::/32 eq telnet any
     

    Specifies deny conditions for the IPv6 access list.

     
    Step 6 exit


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

    Exits IPv6 access list configuration mode and enters global configuration mode.

     
    Step 7 interface type number


    Example: 
    Device(config)# interface Gigabitethernet 1/0/2
     

    Configures an interface and enters interface configuration mode.

     
    Step 8 ipv6 traffic-filter access-list-name {in | out}


    Example: 
    Device(config-if)# ipv6 traffic-filter ipv6acl out
     

    Applies the specified IPv6 access list to the interface configured in Step 7.

     
    Step 9 end


    Example: 
    Device(config-if)# end
     

    Exits interface configuration mode and enters privileged EXEC mode.

     
    Step 10 show ipv6 access-list [access-list-name]


    Example: 
    Device# show ipv6 access-list
     

    Displays the contents of all current IPv6 access lists.

     

    Example:

    The following is sample output from the show ipv6 access-list command: 

    Device# show ipv6 access-list

IPv6 access list ipv6acl
    permit tcp any any eq bgp reflect tcptraffic (8 matches) sequence 10
    permit tcp any any eq telnet reflect tcptraffic (15 matches) sequence 20
    permit udp any any reflect udptraffic sequence 30

IPv6 access list tcptraffic (reflexive) (per-user)
    permit tcp host 2001:DB8:1::32 eq bgp host 2001:DB8:2::32 eq 11000 timeout 300 (time left 243) sequence 1
    permit tcp host 2001:DB8:1::32 eq telnet host 2001:DB8:2::32 eq 11001 timeout 300 (time left 296) sequence 2

IPv6 access list outbound
    evaluate udptraffic
    evaluate tcptraffic

    Configuration Examples for IPv6 Services--Standard Access Control Lists

    Example: Configuring IPv6 Services—Standard Access Control Lists

    Device# configure terminal
Device(config)# ipv6 access-list ipv6acl
Device(config-ipv6-acl)# permit 2001:DB8:1::1/32 any
Device(config-ipv6-acl)# deny tcp 2001:DB8:0300:0201::/32 eq telnet any
Device(config-ipv6-acl)# exit
Device(config)# interface Gigabitethernet 1/0/2
Device(config-if)# ipv6 traffic-filter ipv6acl out
Device(config-if)# end

    Example: Creating and Applying an IPv6 ACL

    The following example shows how to restrict HTTP access to certain hours during the day and log any activity outside of the permitted hours: 

    Device# configure terminal
Device(config)# time-range lunchtime
Device(config-time-range)# periodic weekdays 12:00 to 13:00
Device(config-time-range)# exit
Device(config)# ipv6 access-list OUTBOUND
Device(config-ipv6-acl)# permit tcp any any eq www time-range lunchtime
Device(config-ipv6-acl)# deny tcp any any eq www log-input
Device(config-ipv6-acl)# permit tcp 2001:DB8::/32 any
Device(config-ipv6-acl)# permit udp 2001:DB8::/32 any
Device(config-ipv6-acl)# end

    Additional References for IPv6 Services—Standard Access Control Lists

    Related Documents

    Related Topic

    Document Title

    Cisco IOS commands

    Cisco IOS Master Command List, All Releases

    Security commands

    IPv6 Commands

    Cisco IOS IPv6 Command Reference

    Standards and RFCs

    Standard/RFC

    Title

    RFC 2474

    Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers

    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 Services—Standard Access Control Lists

    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 . An account on Cisco.com is not required.
    Table 1 Feature Information for IPv6 Services—Standard Access Control Lists

    Feature Name

    Releases

    Feature Information

    IPv6 Services—Standard Access Control Lists

    Cisco IOS XE 3.6E

    Access lists determine the type of traffic that is blocked or forwarded at device interfaces. Access control lists (ACLs) allow the filtering of inbound and outbound traffic based on source and destination addresses at interfaces. Standard IPv6 ACLs support traffic filtering based on IPv6 option headers and optional, upper-layer protocol type information.

    In Cisco IOS XE Release 3.6E, this feature is supported on Cisco Catalyst 3850 Series Switches.

    The following commands were introduced or modified: ipv6 access-list, show ipv6 access-list.