Setting Up an IPv4/IPv6 Dual-Stack Network in a VPC

• Only ECSs with certain flavors support IPv6. You need to select such an ECS to use an IPv4/IPv6 dual-stack network.

  On the ECS console, click Create ECS. On the displayed page, check the ECS flavors. If Yes is shown in the IPv6 column, the ECS with this flavor supports IPv6.

• The network planning in this example is for your reference only. Once a VPC and subnet are created, the CIDR blocks cannot be changed. Before creating VPCs, determine how many VPCs and subnets, and what CIDR blocks or connectivity options you will need.

1. Log in to the management console.
2. Click in the upper left corner to display the service list and choose Networking > Virtual Private Cloud.

   The Virtual Private Cloud page is displayed.

3. Click Create VPC.

   The Create VPC page is displayed.

4. On the Create VPC page, set parameters as needed.

   In this example, you need to create a VPC and subnet, and enable IPv6 for this subnet.

   Table 1 VPC parameters

   Parameter	Example Value	Description
   Region	-	The region where the VPC is created. Select the region nearest to you to ensure the lowest possible latency. The VPC, ECS, and EIP used in this example must be in the same region. The region cannot be changed after the VPC is created.
   Name	VPC-A	The VPC name. The name can be modified after the VPC is created.
   IPv4 CIDR Block	192.168.0.0/16	The IPv4 CIDR block of the VPC. You are advised to select from the following CIDR blocks: 10.0.0.0/8–24: The IP address range is from 10.0.0.0 to 10.255.255.255, and the netmask ranges from 8 to 24. 172.16.0.0/12–24: The IP address range is from 172.16.0.0 to 172.31.255.255, and the netmask ranges from 12 to 24. 192.168.0.0/16–24: The IP address range is from 192.168.0.0 to 192.168.255.255, and the netmask ranges from 16 to 24. The CIDR block cannot be changed after the VPC is created.
   Enterprise Project	default	The enterprise project by which resources are centrally managed. Select an existing enterprise project for the VPC. The enterprise project cannot be changed after the VPC is created.
   Advanced Settings (Optional) > Tag	No configuration is required.	The tag that is used to classify and identify resources. Add tags to the VPC as required. After the VPC is created, you can edit tags added to the VPC.
   Advanced Settings (Optional) > Description	No configuration is required.	Supplementary information about the VPC. Enter a description as required. This parameter can be changed after the VPC is created.

   Table 2 Subnet parameters

   Parameter	Example Value	Description
   Name	Subnet-A01	The subnet name. The name can be modified after the subnet is created.
   IPv4 CIDR Block	192.168.0.0/24	The IPv4 CIDR block of the subnet, which is a unique CIDR block with a range of IP addresses in the VPC. The CIDR block cannot be changed after the subnet is created.
   IPv6 CIDR Block (Optional)	Enabled	Whether to automatically assign an IPv6 CIDR block to the subnet. You can enable or disable this option after the subnet is created.
   Associated Route Table	Default	The default route table that the subnet is associated with. Each VPC comes with a default route table. Subnets in the VPC are then automatically associated with the default route table. The default route table has a preset system route that allows subnets in a VPC to communicate with each other. After the subnet is created, you can create a custom route table and associate the subnet with it.
   Advanced Settings (Optional) > Gateway	192.168.0.1	The gateway address of the subnet. You are advised to retain the default address. The gateway address cannot be changed after the subnet is created.
   Advanced Settings (Optional) DNS Server Address Domain Name	No configuration is required.	The parameters that are configured for the ECS in the VPC. In this example, retain the default values or leave them blank. You can change the values after the subnet is created.
   Advanced Settings (Optional) > Tag	No configuration is required.	The tag that is used to classify and identify resources. Add tags to the subnet as required. After the subnet is created, you can edit tags added to the subnet.
   Advanced Settings (Optional) > Description	No configuration is required.	Supplementary information about the subnet. Enter a description as required. The description can be modified after the subnet is created.

5. Click Create Now.

   You will be redirected to the VPC list, where you can find VPC-A you have created.

1. Click in the upper left corner to display the service list and choose Computing > Elastic Cloud Server.

   The Elastic Cloud Server page is displayed.

2. Click Create ECS.

   The Create ECS page is displayed.

3. On the Create ECS page, set parameters as required.

   In this example, set the ECS name to ECS-A01 and configure other parameters as follows:

   • Network: Select VPC-A and Subnet-A01 you have created.

     Select Automatically assign IP address and Automatically-assigned IPv6 address. An IPv4 address and an IPv6 address will be assigned to ECS-A01.

   • Security Group: Create security group Sg-A and add inbound and outbound rules to it. Each security group comes with system rules. You need to check and modify the rules as required to ensure that all rules in Table 3 are added.

     Table 3 Sg-A rules

     Direction	Action	Type	Protocol & Port	Source/Destination	Description
     Inbound	Allow	IPv4	TCP: 22	Source: 10.1.0.7/32	Allows the local PC (10.1.0.7/32) to remotely log in to the Linux ECS over SSH port 22 using IPv4 addresses.
     Inbound	Allow	IPv4	TCP: 3389	Source: 10.1.0.7/32	Allows the local PC (10.1.0.7/32) to remotely log in to the Windows ECS over RDP port 3389 using IPv4 addresses.
     Inbound	Allow	IPv4	ICMP: All	Source: 0.0.0.0/0	Allows IPv4 ping traffic to the ECS in the security group over all ICMP ports to test network connectivity.
     Inbound	Allow	IPv4	All	Source: current security group (Sg-A)	Allows the ECSs in Sg-A to communicate with each other using IPv4 addresses.
     Inbound	Allow	IPv6	All	Source: current security group (Sg-A)	Allows the ECSs in Sg-A to communicate with each other using IPv6 addresses.
     Outbound	Allow	IPv4	All	Destination: 0.0.0.0/0	Allows the ECS in Sg-A to access the external networks using the IPv4 address.
     Outbound	Allow	IPv6	All	Destination: ::/0	Allows the ECS in Sg-A to access the external networks using the IPv6 address.

   • EIP: Select Not required.

4. Log in to ECS-A01 and check whether the ECS has obtained an IPv6 address.
   • By default, dynamic IPv6 address assignment is enabled for Windows public images.
   • Before enabling dynamic IPv6 address assignment for a Linux public image, check whether IPv6 protocol stack is supported first. All Linux public images support the IPv6 protocol stack. You also need to configure the ECS as instructed in section "Dynamically Assigning IPv6 Addresses" in the Elastic Cloud Server User Guide. Otherwise, the ECS cannot communicate with others using IPv6 addresses.

Buy an EIP and bind it to the ECS so that the ECS can communicate with the Internet using the IPv4 address.

1. Click in the upper left corner to display the service list and choose Networking > Elastic IP.

   The EIP list is displayed.

2. Click Assign EIP.

   The Assign EIP page is displayed.

3. On the Assign EIP page, configure the parameters as prompted.
4. Click Create Now.

   Return to the EIP list to view EIP-A you have assigned.

5. In the EIP list, locate EIP-A and click Bind in the Operation column.

   The Bind EIP dialog box is displayed.

6. In the displayed dialog box, select ECS-A01 and click OK.

   Return to the EIP list. You can see that ECS-A01 is displayed in the Associated Instance column in the EIP list.

Buy a shared bandwidth and add the IPv6 address of the ECS to the shared bandwidth so that the ECS can communicate with the Internet using the IPv6 address.

1. Click in the upper left corner to display the service list and choose Networking > Elastic IP.

   The EIP list is displayed.

2. In the navigation pane on the left, choose Shared Bandwidths and click Assign Shared Bandwidth.

   The Assign Shared Bandwidth page is displayed.

3. On the displayed page, set the shared bandwidth name to bandwidth-A and configure other parameters as required.
4. Click Create Now.

   Return to the shared bandwidth list to view Bandwidth-A you have assigned.

5. Click Add Public IP Address in the Operation column.

   The Add Public IP Address dialog box is displayed.

6. Configure the parameters and click OK.
   • Public IP Address: Select IPv6 Address.
   • VPC: Select VPC-A.
   • Subnet: Select Subnet-A01.
   • IPv6 Address: Select the IPv6 address assigned to ECS-A01.

1. Use the local PC to log in to ECS-A01 using the IPv4 EIP and IPv6 address.

   To remotely log in to ECS-A01 using PuTTY:

   • Enter the EIP of ECS-A01 under Host Name (or IP address), for example, 1.95.44.XX.
   • Enter the IPv6 address of ECS-A01 under Host Name (or IP address), for example, 2407:XXX:e857.

   Figure 1 PuTTY configurations

   
   
2. Check whether ECS-A01 can communicate with the Internet using IPv4 and IPv6 addresses.
   • Check whether ECS-A01 can communicate with the Internet using the IPv4 address:

     ping <IPv4-EIP or Domain-name>

   • Check whether ECS-A01 can communicate with the Internet using the IPv6 address:

     ping6 <IPv6-address>

     In this example, 2002:20::45 is used as a public IP address. An example command is as follows:

     ping6 2002:20::45

     If information similar to the following is displayed, ECS-A01 can communicate with the Internet using the IPv6 address.

     [root@ecs-a01 ~]# ping6 2002:20::45
     PING 2002:20::45(2002:20::45) from 2002:20::45 : 56 data bytes
     64 bytes from 2002:20::45: icmp_seq=1 ttl=64 time=0.770 ms
     64 bytes from 2002:20::45: icmp_seq=2 ttl=64 time=0.295 ms
     64 bytes from 2002:20::45: icmp_seq=3 ttl=64 time=0.245 ms
     ^C
     --- 2002:20::45 ping statistics ---
     3 packets transmitted, 3 received, 0% packet loss, time 2080ms
     rtt min/avg/max/mdev = 0.245/0.436/0.770/0.237 ms