Access Control List
Access control lists (ACLs) perform packet filtering to control which packets move through a network and to where. The packet filtering provides security by helping to limit the network traffic, restrict the access of users and devices to a network, and prevent the traffic from leaving a network.
ACL filters:
Inbound ACLs filter the traffic before router makes forward decision.
Outbound ACLs filter the traffic after the router makes forward decision.
An ACL filter condition has to two actions; permit and deny. We can permit certain types of traffic while blocking rest or we can block certain types of traffic while allowing rest.
Example Network setup in NetSim:
Create a scenario as per the below screenshot
Go to router properties and enable ACL_Status shown below
Set the ACL properties as per the following screenshot and click on ADD which permits traffic from Wired Node 2 (11.1.1.2) to Wired Node 3 (11.2.1.2) in Router's interface 2
Similarly Set the following properties and click on ADD which denies traffic from Wired Node 2 (11.1.1.2) to Wired Node 4 (11.3.1.2) in Router's interface 3
Set the following properties and click on ADD and then ACCEPT which permits traffic from Wired node 3 (11.2.1.2) to Wired Node 4 (11.3.1.2) in Router's interface 3
Simulate the network and observe the application throughput.
The throughput for the second application is zero since the ACL blocks traffic flow in the Router's 3rd interface
Related articles:
what-are-the-access-control-list-options-in-netsim-and-where-is-the-code-for-this-
how-to-configure-acl-with-respect-to-port-numbers-and-protocols-in-netsim-