Creating a Network ACL

Scenarios

A security group protects the instances in it, such as ECSs, databases, and containers, while a network ACL protects associated subnets and all the instances in the subnets. Security groups are mandatory, while network ACLs are optional. If you want to add an additional layer of protection, you can create a network ACL and associate it with one or more subnets. Network ACLs and security groups can be used together for fine-grained and comprehensive access control.

Procedure

1. Go to the network ACL list page.
2. In the upper right corner of the network ACL list, click Create Network ACL.
3. On the displayed page, configure the parameters as prompted.

   Table 1 Parameter descriptions

   Parameter	Description	Example Value
   Name	Mandatory The network ACL name. The name can contain a maximum of 64 characters, which may consist of letters, digits, underscores (_), hyphens (-), and periods (.). The name cannot contain spaces.	fw-A
   Description (Optional)	Supplementary information about the network ACL. This parameter is optional. The description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).	N/A

4. Click OK.
5. Click OK.

Follow-up Operations

1. A new network ACL comes with default inbound and outbound rules that deny all traffic in and out of associated subnets. You can add custom rules to allow traffic by referring to Adding a Network ACL Rule. Traffic will preferentially match the custom rules.
2. You need to associate the enabled network ACL with the subnets by referring to Associating Subnets with a Network ACL.