Updated on 2024-07-12 GMT+08:00

Adding a Network ACL Rule (Default Priorities)

Scenarios

You can add inbound and outbound rules to a network ACL to control the traffic in and out of a subnet.

When you perform the following operations to add a rule, the system generates a priority based on the sequence when the rule is added. You cannot specify a priority.

As shown in Table 1, there are two custom inbound rules (rule A and rule B) and one default rule. The priority of rule A is 1 and that of rule B is 2. The default rule has the lowest priority. If rule C is added, the system sets its priority to 3, which has lower priority than rules A and B and higher priority than the default rule.

Table 1 Default priorities

Priorities (Rules A and B)

Priorities (Rules A, B, and C)

Custom rule A

1

Custom rule A

1

--

--

Custom rule B

2

Custom rule B

2

Custom rule C

3

Default rule

*

Default rule

*

If the default priorities do not meet your requirements, you can customize the priorities by referring to Adding a Network ACL Rule (Custom Priorities).

Notes and Constraints

A network ACL can contain up to 100 rules in one direction, or performance will deteriorate.

Procedure

  1. Log in to the management console.
  1. Click in the upper left corner and select the desired region and project.
  2. Click in the upper left corner and choose Networking > Virtual Private Cloud.

    The Virtual Private Cloud page is displayed.

  3. In the navigation pane on the left, choose Access Control > Network ACLs.

    The network ACL list is displayed.

  4. In the network ACL list, locate the target network ACL and click its name.

    The network ACL summary page is displayed.

  5. On the Inbound Rules or Outbound Rules tab, click Add Rule.

    The Add Inbound Rule or Add Outbound Rule dialog box is displayed.

  6. Configure required parameters.
    • Click to add more rules.
    • Locate the row that contains the network ACL rule and click Replicate in the Operation column to replicate an existing rule.
    Table 2 Parameter descriptions

    Parameter

    Description

    Example Value

    Type

    Network ACL type. There are two options:
    • IPv4
    • IPv6

    IPv4

    Action

    The action in the network ACL. There are two options:
    • Allow: allows matched traffic in and out of a subnet.
    • Deny: denies matched traffic in and out of a subnet.

    Allow

    Protocol

    The protocol supported by the network ACL to match traffic. The value can be TCP, UDP, or ICMP.

    TCP

    Source

    The source from which the traffic is allowed. The source can be an IP address or IP address range.

    • IP address:
      • Single IP address: 192.168.10.10/32 (IPv4); 2002:50::44/128 (IPv6)
      • All IP addresses: 0.0.0.0/0 (IPv4); ::/0 (IPv6)
      • IP address range: 192.168.1.0/24 (IPv4); 2407:c080:802:469::/64 (IPv6)

    192.168.0.0/24

    Source Port Range

    The source port or port range used to match traffic. The value ranges from 1 to 65535.

    22-30

    Destination

    The destination to which the traffic is allowed. The destination can be an IP address or IP address range.

    • IP address:
      • Single IP address: 192.168.10.10/32 (IPv4); 2002:50::44/128 (IPv6)
      • All IP addresses: 0.0.0.0/0 (IPv4); ::/0 (IPv6)
      • IP address range: 192.168.1.0/24 (IPv4); 2407:c080:802:469::/64 (IPv6)

    0.0.0.0/0

    Destination Port Range

    The destination port or port range used to match traffic. The value ranges from 1 to 65535.

    22-30

    Description

    Supplementary information about the network ACL rule. This parameter is optional.

    The description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).

    N/A

  7. Click OK.

    Return to the rule list to check the new rule.

    • The system generates priorities based on the sequence when rules are added. The rule that is added earlier is preferentially matched.
    • If the status of the new rule is Enabled, the rule is applied.