How to Implement IPv6 ACLs on Cisco Routers

Implementing IPv6 access control lists (ACLs) on Cisco routers allows you to filter IPv6 traffic based on specified criteria. Here’s a step-by-step guide:

Step 1: Access the Router’s CLI

Connect to your Cisco router using a console cable or through SSH/Telnet.

Step 2: Enter Privileged Exec Mode

enable

Provide the enable password if prompted.

Step 3: Enter Global Configuration Mode

configure terminal

Step 4: Create an IPv6 ACL

ipv6 access-list <acl-name> [sequence-number]

Replace with the desired name of the IPv6 ACL and optionally specify a if you want to insert an entry at a specific position.

Example:

ipv6 access-list MY_ACL

Step 5: Define Permit or Deny Statements

permit|deny <protocol> <source-address> <source-wildcard> <destination-address> <destination-wildcard>

Replace with the desired protocol (e.g., tcp, udp, icmp, ipv6), and with the source and destination IPv6 addresses, and and with the corresponding wildcard masks.

Example (permit ICMP traffic from any source to any destination):

permit icmp any any

Step 6: Apply the ACL to an Interface

interface <interface-type> <interface-number>
ipv6 traffic-filter <acl-name> {in|out}

Replace with the specific interface and with the name of the IPv6 ACL. Choose whether to apply the ACL to inbound (in) or outbound (out) traffic.

Example (applying the ACL to the inbound direction on GigabitEthernet0/0):

interface GigabitEthernet0/0
ipv6 traffic-filter MY_ACL in

Step 7: Save Configuration

write memory

or

copy running-config startup-config

Important Notes:

• Ensure that your router supports IPv6 and that it’s running a compatible IOS version.
• ACL entries are processed in order. Make sure to place more specific entries before less specific ones.
• Be careful when applying ACLs, as they can impact traffic flows.
• Always consult the documentation for your specific router model and IOS version if you encounter any issues. The exact commands and syntax might vary depending on the specific Cisco router model and IOS version you are using.