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Example Custom Route Outside a VPC

A custom route outside a VPC routes traffic originating outside the VPC to specified ECSs in the VPC. When adding this type of route, you can set Destination to the default value 0.0.0.0/0 or a specific network segment. However, the network segment cannot conflict with subnet CIDR blocks in the VPC. The destination of each custom route must be unique.

Custom Route Between VPCs

Example scenario

If a VPC peering connection has been created linking two VPCs, VPC1 and VPC2, but only VPC1 has Internet access, you can add a custom route to allow the ECSs in VPC2 to access the Internet through an ECS that has an EIP bound in VPC1.

Figure 1 Custom Route Between VPCs

Configuration

  1. Create a VPC peering connection between VPC1 and VPC2. Figure 2 shows the VPC peering connection configuration.
    Figure 2 VPC peering connection between VPC1 and VPC2

    Table 1 and Table 2 list the routes used to configure the VPC peering connection.

    Table 1 Route of a VPC peering connection in the route table associated with Subnet A

    Destination

    Next Hop

    192.168.10.0/24

    pc-01
    Table 2 Route of a VPC peering connection in the route table associated with Subnet X

    Destination

    Next Hop

    192.168.1.0/24

    pc-01

    0.0.0.0/0

    pc-01

    In the preceding route tables, value pc-01 indicates the VPC peering connection ID. The value is automatically generated and cannot be configured.

  1. Table 3 lists the custom route table configuration.
    Table 3 Custom route in the VPC1 default route table

    Destination

    Next Hop

    0.0.0.0/0

    The private or virtual IP address of ECS1
    • When you use a custom route to access the Internet, the destination can only be set to default value 0.0.0.0/0. It cannot be set to a specific public network segment.
    • If the next hop is a virtual IP address, the virtual IP address must have an EIP bound. Otherwise, access to the Internet through this virtual IP address is not possible.
  2. Configure ECS1 as an SNAT server by following the instructions provided in Configuring an SNAT Server.

Custom Route Between a VPC and a Direct Connect Connection

Example scenario

You can add a custom route to forward all packets from a Direct Connect connection to specified servers in the VPC, but a custom route needs to be added to the VPC. Table 4 provides the details needed to configure the route.

Figure 3 Custom route between a VPC and a Direct Connect connection

Configuration

  1. Table 4 lists the custom route configuration. The destination is default value 0.0.0.0/0, and the next hop is the ECS private or virtual IP address.
    Table 4 VPC custom route table

    Destination

    Next Hop

    0.0.0.0/0

    The private or virtual IP address of ECS
  2. Configure ECS1 as an SNAT server by following the instructions provided in Configuring an SNAT Server.
Parent topic: Route Table