Network Configurations

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 network, including subnet and security group, for an ECS.

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

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

   

   • Ensure that DHCP is enabled in the VPC to which the ECS belongs.
   • 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 expansion NICs to an ECS and specify IP addresses for them (including primary NICs).
   

   When you specify an IP address for a NIC, if multiple ECSs are created 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.
   • This subnet cannot duplicate a subnet with a specified start IP address.
   • Automatically-assigned IP address: This parameter is available only if an SN3 ECS is selected and IPv6 is enabled in the VPC subnet. For instructions about how to enable IPv6 on a subnet, see IPv4 and IPv6 Dual-Stack Network.

     By default, the system assigns IPv4 addresses. After Automatically-assigned IP address is selected, 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.

     

     • IPv4 and IPv6 dual-stack is at open beta test only in the CN North-Beijing4 region and will be offered in other regions later.
     • IPv6 can be enabled only during ECS creation, and the configuration cannot be modified. If IPv6 Bandwidth is not enabled when you create an ECS, you can enable it after the ECS is created.
     • Only SN3 ECSs can use IPv6 addresses.
     • 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.

   Security group rules determine ECS access and usage. For instructions about how to configure a security group rule, see Adding a Security Group Rule. Enable protocols and ports as needed. Common protocols and ports are as follows:

   • Port 80: default port for web page access through HTTP.
   • Port 443: web page access through HTTPS.
   • ICMP: checks communication statuses between ECSs through ping operations.
   • Port 22: reserved for logging in to a Linux ECS using SSH.
   • Port 3389: reserved for logging in to a Windows ECS using SSH.
   

   Before initializing an ECS, ensure that the security group rule in the outbound direction meets the following requirements:

   • Protocol: TCP
   • Port Range: 80
   • Remote End: 169.254.0.0/16

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

   • Protocol: ANY
   • Port Range: 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:

   • Not required

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

   • Auto assign

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

   • Use existing

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

   

   If the ECS to be created will be used as an email server, you are advised to configure reverse domain name resolution for the EIP. Reverse domain name resolution minimizes the possibility that mails sent by an email server are regarded as junk mails. For more information, see Configuring a PTR Record.

5. Set EIP Type.
   • Static BGP offers routing control and protects against route flapping, but cannot choose an optimal path in real time when a network connection fails.
   • Dynamic BGP provides automatic failover and chooses the optimal path when a network connection fails.
6. Set Billed By.

   This parameter is mandatory if EIP is set to Auto assign. If you select Bandwidth or Traffic, the system will allocate a dedicated bandwidth for you, and the bandwidth is dedicated for one EIP.

   • Bandwidth: The billing will be based on the duration for which the bandwidth is used.
   • Traffic: The billing will be based on the total traffic irrespective of the duration for which the bandwidth is used.
   • Shared bandwidth: The bandwidth can be used by multiple EIPs.
     

     • A bandwidth can be shared between a limited number of EIPs. If the number of EIPs cannot meet service requirement, switch to a higher shared bandwidth or apply for expanding the EIP quota of the existing bandwidth.
     • EIPs that are billed yearly/monthly do not support shared bandwidths.
     • When a shared bandwidth that is billed yearly/monthly expires, the system automatically deletes the bandwidth configuration and creates a dedicated bandwidth billed by traffic for the EIPs sharing the deleted bandwidth configuration.
7. Click Next: Configure Advanced Settings or Confirm.