Security Configuration Guide: Access Control Lists, Cisco IOS XE Release 3S
IPv6 Access Control Lists
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IPv6 Access Control Lists

Access lists determine what traffic is blocked and what traffic is forwarded at router interfaces and allow filtering of traffic based on source and destination addresses, and inbound and outbound traffic to a specific interface. Standard IPv6 ACL functionality was extended to support traffic filtering based on IPv6 option headers and optional, upper-layer protocol type information for finer granularity of control. Standard IPv6 ACL functionality was extended to support traffic filtering based on IPv6 option headers and optional, upper-layer protocol type information for finer granularity of control.

This module describes how to configure IPv6 traffic filtering and to control access to virtual terminal lines.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Information About IPv6 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 router 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 all used for IPv6 inspection--traffic class, flow label, payload length, next header, hop limit, and source or destination 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 router 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 router address on the interface. If the IPv6 ACL is applied to outbound traffic, the source address in the ACL is matched against the local router 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.

Tunneling Support

IPv6 packets tunneled in IPv4 are not inspected. If a tunnel terminates on a router, and IPv6 traffic exiting the tunnel is nonterminating, then the traffic is inspected.

Virtual Fragment Reassembly

When VFR is enabled, VFR processing begins after ACL input lists are checked against incoming packets. The incoming packets are tagged with the appropriate VFR information.

SSO ISSU Support for Per-User IPv6 ACL for PPP Sessions

The SSO/ISSU Support for per-User IPv6 ACL for PPP Sessions feature reproduces IPv6 ACLs on the active Route Processor to the standby RP and provides a consistent stateful switchover and in-service software upgrade experience for active sessions. The feature also extends the ability to maintain Template ACLs (IPv6 only or dual stack) through ISSU and SSO.

Both named and tagged ACLs can be configured and applied in the following ways:

  • Virtual-template ACL:
    • Virtual-template ACLs (also called interface ACLs) are configured under a virtual-template definition on the ISG router.
    • Only named ACLs can be configured under a virtual-template definition. Named ACLs applied to virtual templates get cloned to all virtual access interfaces created using that virtual-template definition.
  • Per-user ACLs are always applied through RADIUS:
    • User profile--The ACL is configured in the user profile on RADIUS and is applied when the session is up.
    • Change of Authorization (CoA) per-user push--The ACL is applied through a RADIUS CoA push from a subscriber profile.

The table below shows information about support for functionality and SSO for these ACL configurations:

Table 1 SSO Support for Named and Tagged ACLs

ACL Configuration

Functionality Supported

SSO Supported

Named ACL

Virtual-Template

Yes

Yes

User Profile

Yes

Yes

CoA per-User Push

Yes

No

Tagged ACL

Virtual-Template

No

No

User Profile

Yes

Yes

CoA per-User Push

Yes

No

How to Configure IPv6 Access Control Lists

Configuring IPv6 Traffic Filtering

Creating and Configuring an IPv6 ACL for Traffic Filtering


Note

IPv6 ACLs on the Cisco ASR 1000 platform do not contain implicit permit rules. The IPv6 neighbor discovery process uses the IPv6 network-layer service; therefore, to enable IPv6 neighbor discovery, you must add IPv6 ACLs to allow IPv6 neighbor discovery packets to be sent and received on an interface. In IPv4, the Address Resolution Protocol (ARP), which is equivalent to the IPv6 neighbor discovery process, uses a separate data-link-layer protocol; therefore, by default IPv4 ACLs implicitly allow ARP packets to be sent and received on an interface.

>
SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ipv6 access-list access-list-name

    4.    Do one of the following:

    • permit protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix / prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name]
    • deny protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | doh-type] ] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name] [undetermined-transport


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 ipv6 access-list access-list-name


    Example:
    Router(config)# ipv6 access-list outbound
     

    Defines an IPv6 ACL, and enters IPv6 access list configuration mode.

    • The access-list nameargument specifies the name of the IPv6 ACL. IPv6 ACL names cannot contain a space or quotation mark, or begin with a numeral.
     
    Step 4Do one of the following:
    • permit protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix / prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name]
    • deny protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | doh-type] ] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name] [undetermined-transport


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


    Example:
    

        
    
 

    Example:
    
          
              
    

        
    
 

    Example:
    
          
    Router(config-ipv6-acl)# deny tcp host 2001:DB8:1::1 any log-input
    

        
    
 
          		 
          
    
Specifies permit or deny conditions for an IPv6 ACL.
    

         
      
    

    

    

    

    Applying the IPv6 ACL to an Interface
    

    SUMMARY STEPS
      1.   
      
          
            enable
          
        
      

      2.   
      
          
            configure
          
          
            terminal
          
        
      

      3.   
      
          
            interface
          
          
            type
            number
          
        
      

      4.   
      
          
            ipv6
            traffic-filter
          
          
            access-list-name
          {in| out}
      


    DETAILED STEPS
       Command or ActionPurpose
      Step 1
          
            enable
          
        
       

      Example:
      
          
      Router> enable
      

        
      
 
            		 
          
      
Enables privileged EXEC mode. 
      

          
      • 
Enter your password if prompted.

        • 

      

         
      
      

      Step 2
          
            configure
          
          
            terminal
          
        
       

      Example:
      
          
      Router# configure terminal
      

        
      
 
            		 
          
      
Enters global configuration mode.
      

         
      
      

      Step 3
          
            interface
          
          
            type
            number
          
        
       

      Example:
      
          
      Router(config)# interface gigabitethernet 0/0/0
      

        
      
 
            		 
          
      
Specifies the interface type and number, and enters interface configuration mode.
      

         
      
      

      Step 4
          
            ipv6
            traffic-filter
          
          
            access-list-name
          {in| out}
       

      Example:
      
          
      Router(config-if)# ipv6 traffic-filter outbound out
      

        
      
 
            		 
          
      
Applies the specified IPv6 access list to the interface specified in the previous step.
      

         
      
      

      

      

      

      

      Controlling Access to a vty
      

      

      Creating an IPv6 ACL to Provide Access Class Filtering
      

      SUMMARY STEPS
        1.   
      
          
            enable
          
        
        

        2.   
      
          
            configure
          
          
            terminal
          
        
        

        3.   
      
          
            ipv6
            access-list
          
          
            access-list-name
          
        
        

        4.   
      Do one of the following:
        • 
            
              permit
              protocol
             {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix / prefix-length | any | host destination-ipv6-address}
 [operator 
[port-number]] [dest-option-type 
[doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name
          • 

        • 
          
          • 

        • 
          
          • 

        • 
            
              deny
            
            
              protocol
             {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator 
[port-number]] [dest-option-type [doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name] [undetermined-transport
          • 

        

        


      DETAILED STEPS
         Command or ActionPurpose
        Step 1
          
            enable
          
        
         

        Example:
        
          
        Router> enable
        

        
        
 
              		 
          
        
Enables privileged EXEC mode. 
        

          
        • 
Enter your password if prompted.

          • 

        

         
      
        

        Step 2
          
            configure
          
          
            terminal
          
        
         

        Example:
        
          
        Router# configure terminal
        

        
        
 
              		 
          
        
Enters global configuration mode.
        

         
      
        

        Step 3
          
            ipv6
            access-list
          
          
            access-list-name
          
        
         

        Example:
        
          
        Router(config)# ipv6 access-list cisco
        

        
        
 
              		 
          
        
Defines an IPv6 ACL, and enters IPv6 access list configuration mode.
        

         
      
        

        Step 4Do one of the following:
        • 
            
              permit
              protocol
             {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix / prefix-length | any | host destination-ipv6-address}
 [operator 
[port-number]] [dest-option-type 
[doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name
          • 

        • 
          
          • 

        • 
          
          • 

        • 
            
              deny
            
            
              protocol
             {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator 
[port-number]] [dest-option-type [doh-number | doh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] [mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] [sequence value] [time-range name] [undetermined-transport
          • 

        
 

        Example:
        
          
        Router(config-ipv6-acl)# permit ipv6 host 2001:DB8:0:4::32 any eq telnet
        

        
        
 

        Example:
        
          
        

        
        
 

        Example:
        
          
                  
        

        
        
 

        Example:
        
          
        Router(config-ipv6-acl)# deny ipv6 host 2001:DB8:0:6::6/32 any
        

        
        
 
              		 
          
        
Specifies permit or deny conditions for an IPv6 ACL.
        

         
      
        

        

        

        

        Applying an IPv6 ACL to the Virtual Terminal Line
        

        SUMMARY STEPS
          1.   
      
          
            enable
          
        
          

          2.   
      
          
            configure
          
          
            terminal
          
        
          

          3.   
      
          
            line
          [aux| console| tty| vty] line-number[ending-line-number]
          

          4.   
      
          
            ipv6
            access-class
          
          
            ipv6-access-list-name
          {in| out}
          


        DETAILED STEPS
           Command or ActionPurpose
          Step 1
          
            enable
          
        
           

          Example:
          
          
          Router> enable
          

        
          
 
                		 
          
          
Enables privileged EXEC mode. 
          

          
          • 
Enter your password if prompted.

            • 

          

         
      
          

          Step 2
          
            configure
          
          
            terminal
          
        
           

          Example:
          
          
          Router# configure terminal
          

        
          
 
                		 
          
          
Enters global configuration mode.
          

         
      
          

          Step 3
          
            line
          [aux| console| tty| vty] line-number[ending-line-number]
           

          Example:
          
          
          Router(config)# line vty 0 4
          

        
          
 
                		 
          
          
Identifies a specific line for configuration and enters line configuration mode.
          

          
          • 
In this example, the vty keyword is used to specify the virtual terminal lines for remote console access.

            • 

          

         
      
          

          Step 4
          
            ipv6
            access-class
          
          
            ipv6-access-list-name
          {in| out}
           

          Example:
          
          
          Router(config-line)# ipv6 access-class cisco in
          

        
          
 
                		 
          
          
Filters incoming and outgoing connections to and from the router based on an IPv6 ACL.
          

         
      
          

          

          

          

          

          

          Configuration Examples for IPv6 Access Control Lists
          

          Example: Verifying IPv6 ACL Configuration
          

           
		
           In this example, the 
		  show ipv6 access-list command is used to verify that IPv6 ACLs are configured correctly: 
		
          
 
		
          Router> show ipv6 access-list

IPv6 access list inbound
    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
          
 
	 
          

          

          

          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
          
 
	 
          

          

          

          Example  Controlling Access to a vty
          

          
      
          
In the following example, incoming connections to the virtual terminal lines 0 to 4 are filtered based on the IPv6 access list named acl1:
          

      
          ipv6 access-list acl1
 permit ipv6 host 2001:DB8:0:4::2/32 any
!
line vty 0 4
 ipv6 access-class acl1 in
          

    
          

          

          

          

          Additional References
          

           
	 
          

          Related Documents
           
		 
		

           
					 
           Related Topic 
					 
          
 
				            		
 
					 
           Document Title 
					 
          
 
				            		

          
          

           
					 
           Cisco IOS commands 
					 
          
 
				            		
 
					 
           
						Cisco IOS Master Command List, All Releases
          
 
				            		

          

           
					 
           IP access list commands 
					 
          
 
				            		
 
					 
           Cisco IOS Security Command Reference 
						
          
 
				            		

          

           
					 
           Configuring IP access lists 
					 
          
 
				            		
 
					 
           “Creating an IP Access List and Applying It to an Interface”
          
 
				            		

          
          

          

          
 
	 
          

          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 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 
		  www.cisco.com/​go/​cfn. An account on Cisco.com is not required. 
		
          
 
	 
          


          Table 2 Feature Information for IPv6 Access Control Lists
          Feature Name 
			 
          
          		

          Releases 
			 
          
          		

          Feature Information 
			 
          
          		

          
          

           
				
          IPv6 Services: Extended Access Control Lists 
				
          
 
			           		
 
				
          Cisco IOS XE Release 2.1 
				
          
 
			           		
 
				
          Standard IPv6 ACL functionality was extended to support traffic filtering based on IPv6 option headers and optional, upper-layer protocol type information for finer granularity of control. 
				
          
 
			           		

          

           
				
          SSO/ISSU Support for Per-User IPv6 ACL for PPP Sessions 
				
          
 
			           		
 
				
          Cisco IOS XE Release 3.2.1S 
				
          
 
			           		
 
				
          Reproducing IPv6 ACLs on the active RP to the standby RP provides a consistent SSO and ISSU experience for active sessions.