CCNA ACL Lab Questions

CCNA ACL Lab Questions

Are you preparing for the Cisco Certified Network Associate (CCNA) exam and need practice with Access Control Lists (ACLs)? In this blog post, we will provide you with a series of challenging lab questions to help you master the concepts of ACLs and their implementation in routing and switching environments. These questions will cover various topics including ACL types, configuration, and troubleshooting. Let’s dive in!

Question 1:

You are tasked with configuring an extended ACL to permit traffic from only specific source and destination IP addresses. Which command sequence will achieve this on a Cisco router?

access-list 100 permit ip source_ip destination_ip
interface interface_name
ip access-group 100 in

Explanation: The “access-list” command is used to create an extended ACL, where you specify the source and destination IP addresses you want to permit traffic for. Once defined, you need to apply this ACL to the desired interface using the “ip access-group” command.

Question 2:

You have applied an ACL to a router interface, but some hosts are still unable to communicate with each other. What could be the potential cause of this issue and how can you debug it?

Explanation: The most common cause of this issue is an incorrect or incomplete ACL configuration. To debug the problem, you can use the following steps:

  1. Check the ACL configuration for any errors or omissions.
  2. Verify if the ACL is applied to the correct interface.
  3. Check if the ACL is blocking the desired traffic by using the “show access-lists” command.
  4. Review the router’s routing table to ensure that the necessary routes are in place for the traffic to reach its destination.
  5. Consider the order in which ACLs are applied, as the first match is used. If there are overlapping ACL entries, modify them accordingly.

Question 3:

What is the difference between a standard ACL and an extended ACL?

Explanation: Standard ACLs are used to filter traffic based on the source IP address only, whereas extended ACLs provide more granular control by filtering traffic based on source and destination IP addresses, protocols, ports, and other criteria. Extended ACLs offer greater flexibility in defining access control rules but require more careful planning and consideration.

Leave a Comment