Step 2: Configure Network

Network Settings

1. Set Network by selecting an available VPC and subnet from the drop-down list and specifying a private IP address assignment mode.

   VPC provides a dedicated network for your ECS. A VPC can contain subnets for further isolation. You can configure security groups per subnet to control access to cloud resources.

   You can select an existing VPC or create a new one.

   For more information about VPC, see Virtual Private Cloud User Guide.

   

   • Ensure that DHCP is enabled in the VPC which the ECS belongs to.
   • When you use VPC for the first time, the system automatically creates a VPC for you, including the security group and NIC.
2. (Optional) Add an extension NIC. You can add multiple extension NICs to an ECS and specify IP addresses for them (including primary NICs).
   

   If you specify an IP address for a NIC when creating multiple ECSs in a batch:

   • This IP address serves as the start IP address.
   • Ensure that the IP addresses required by the NICs are within the subnet, consecutive, and available.
   • The subnet with the specified IP address cannot overlap with other subnets.
   • IPv6 not required/Automatically-assigned IPv6 address: This parameter is available only if the ECS is of specific flavors and in a VPC with IPv6 enabled. For details about how to enable IPv6 on a subnet, see "IPv4 and IPv6 Dual-Stack Network" in Virtual Private Cloud User Guide. For details about how to check whether an ECS supports IPv4/IPv6 dual stack, see "Constraints" in Dynamically Assigning IPv6 Addresses.

     By default, the system assigns IPv4 addresses. If you select Automatically-assigned IPv6 address, the system assigns IPv6 addresses. In a VPC, an ECS uses an IPv6 address to access the dual-stack intranet. To access the Internet, you must enable IPv6 Bandwidth and select a shared bandwidth. Then, the ECS accesses the IPv6 Internet through the IPv6 address.

     After purchasing an ECS, enable IPv6 so that the ECS dynamically obtains an IPv6 address. For details, see Dynamically Assigning IPv6 Addresses.

     

     • IPv6 can be enabled only during ECS creation, and the configuration cannot be modified after the ECS is created. If IPv6 Bandwidth is not enabled when you create an ECS, you can enable it after the ECS is created.
     • Dedicated bandwidth is not supported.
3. Set Security Group by selecting an available security group from the drop-down list or creating a new one.

   A security group controls ECS access within or between security groups by defining access rules. This enhances ECS security.

   When creating an ECS, you can select multiple (recommended not more than five) security groups. In such a case, the access rules of all the selected security groups apply on the ECS.

   

   Before initializing an ECS, ensure that the security group rules for the outbound direction meet the following requirements:

   • Protocol: TCP
   • Port: 80
   • Source: 169.254.0.0/16

   If you use the default security group rules for the outbound direction, the preceding requirements are met, and the ECS can be initialized. The default security group rules for the outbound direction are as follows:

   • Protocol: ANY
   • Port: ANY
   • Remote End: 0.0.0.0/16
4. Set EIP.

   An EIP is a static public IP address bound to an ECS in a VPC. Using the EIP, the ECS provides services externally.

   The following options are provided:

   • Auto assign

     The system automatically assigns an EIP for the ECS. The EIP provides a dedicated bandwidth that is configurable.

   • Specify

     An existing EIP is assigned for the ECS. When using an existing EIP, you are not allowed to create ECSs in a batch.

   • Do not use

     Without an EIP, the ECS cannot access the Internet and is used in the private network or cluster only.

5. Set Bandwidth Size.

   Select the bandwidth based on service requirements. The unit is Mbit/s.

6. Click Next: Configure Advanced Settings.