Using NAT Gateway and Direct Connect to Accelerate Internet Access

Scenarios

Solution Advantages

Typical Topology

1. Use Direct Connect to connect your IDC to your VPC.
2. Create a NAT gateway in the VPC to connect to the Internet.

   Figure 1 Network topology

   
   

Prerequisites

• The default route of the IDC is available for configuring Direct Connect.
• The network CIDR block of the IDC does not overlap with the subnet CIDR block of the VPC on the cloud. Otherwise, the communication between the IDC and the VPC will fail.

Procedure

1. Create a VPC.

   For details, see section "Creating a VPC" in the Virtual Private Cloud User Guide.

2. Configure a Direct Connect connection.

   Create a Direct Connect connection to connect the IDC to the VPC. For details, see section "Getting Started" in the Direct Connect User Guide

   Note

   Add the 0.0.0.0/0 CIDR block as the local subnet on the cloud when configuring the route for the Direct Connect connection.

   • Static: Add the default route with 0.0.0.0/0 as the destination in the on-premises data center and set the next hop to the connection.
   • BGP: The on-premises network can learn the default route using BGP.

3. Assign an EIP and configure a NAT gateway.
   1. For details, see section "Assigning an EIP" in the Elastic IP User Guide.
   2. Create a NAT gateway. For details, see Creating a NAT Gateway.
   3. Add an SNAT rule with the CIDR block set to that of the Direct Connect connection. For more information, see Adding an SNAT Rule.

      Set CIDR Block to 172.18.0.0/24 and select an EIP.

   4. Add a DNAT rule. For more information, see Adding a DNAT Rule.

      Configure the protocol and port type. All ports is used as an example. Set Private IP Address to 172.18.0.100 and select an EIP.

      Note

      SNAT and DNAT rules are designed for different functions. If SNAT and DNAT rules use the same EIP, resource preemption will occur. An SNAT rule cannot share an EIP with a DNAT rule with Port Type set to All ports.

Verification