When Would A Network Administrator Use The Clear Access-List Counters Command?

When would a network administrator use the clear access-list counters command?

• During the baseline obtaining.
• During low memory buffers.
• During the ACL troubleshooting and want to know how many packets are matched.
• From the ACL when the ACE is deleted.

Answer: The number of the ACE match condition which is made during the particular ACE are reset with the help of the clear access-list counters command.it is effective during the trouble of the ACL which is recently turned to account.

What is an access control list (ACL)?

As the name indicate the access control list is the rules or a list set that is set for the network traffic filtration. The configuration of the ACL happens through the help of the network devices with the abilities of the packet filtering like the router and the firewalls.

It contains the condition lists which divide the packets and help in the determination of the allocation and the denying of the network traffic. They apply to the interface basis of the packets leaving or the entering interface. On the Cisco device two types of ACLs are present:

Standard access list: It helps in the evaluation of the source IP address for the packets.it is not so powerful as the extended access list but it is less CPU concentrated for the device.

Extended access list: It helps in the determination of the source and the destination address, layer 3 protocol types, port of the source and the destination, and various other parameters. The extended ACL is complicated in configuration and needs more CPU time them the normal ACLs, but it gives the control on a granular level.

How to Troubleshoot the ACL issues?

Somehow the ACLs are very difficult to troubleshoot, in the structure of the design it can control the network traffic and as the result, it causes the issue on the particular traffic. The 3 steps procedure help in the determination of whether the ACL is to blame in the issue related to the network:

Step 1: regulate the interface which has the ACLs

The first try to find whether the ACL is applied to the experiencing issue of the network during the router configuration. On the Cisco IOS command, two commands are helpful in the evaluation:

• Show run interface.
• Show IP interface.

Step:2 evaluate when the ACL statement is affecting the traffic

Evaluate the ACL which are affecting the network and the particular person who is experiencing the issue, determine or experiencing. Some of the commands for the evaluation are in the following:

• Show access list.
• Shoe io access-list.

Step 3: Check the ACLs to match the traffic

This step determines the type of traffic which is sent to UDP, TCP, or the ICMP. Do any modern ACLs which would alter the traffic? ICMP is come under its types and not in the TCP or UDP.

Step:4 Some of the facts which remember about ACLs

ACLs procedure on the logic of the first-match logic which means ACL 1 is processed before the ACL 2 and so on. The TCP or UDP are used in the commands of the ACL when the port numbers are checked. use the explicit deny for the ACL counter increments.