Section 2: Why Use NACLs?

Section 1: What Are Network Access Control Lists (NACLs)?

One such feature of security provided by AWS(Amazon Web Services) is the Network Access Control List(NACL). This NACL is defined by default for every Virtual Private Network(VPC). However, you can create custom NACL according to your requirements. These NACL define inbound and outbound rule for subnets present in VPC. These have almost the same function as Security Groups the only difference is NACL works in subnet levels and Security groups are defined for instances and other resources....

Section 2: Why Use NACLs?

Example 1:...

Section 3: Key Concepts and Terminologies

Rule Number: Rules can be numbered starting from 1 to 32766. It is evaluated in ascending order, which means from lower to higher. If a lower numbered rule is matched with the traffic, it is applied regardless of any higher numbered rule, contradicting it. Protocol: You can specify the protocol of the traffic that should match (EX: ICMP,TCP). Port Number: To specify the listening port.(Ex: Port 80 for HTTP) Source: This is for inbound rules only to specify the source with what CIDR value is allowed. Destination: This is for outbound rules only to specify the destination with what CIDR value is allowed. Type: The type of traffic can be All traffic or specific such as “SSH”. Allow/Deny: To Specify whether to allow or deny the traffic....

Section 4: Creating and Managing NACLs

Step 1: In AWS first create a VPC...

Section 5: Testing NACL

Now create a instance under the same subnet with default security group(in order to understand how NACL works however the best practice is to use own Security Group)...

FAQs On NACL

1. How Does An NACL Differ From A Security Group?...