This topic explains why you cannot ping an ECS instance from a PC and how to troubleshoot it.

Symptoms

A PC cannot connect to Alibaba Cloud through an SAG-1000 device. For example, you cannot ping an ECS instance in the same CEN from the PC.

Causes

  • The link between the PC and the SAG-1000 is faulty.
  • The VPN link between the SAG and Alibaba Cloud is faulty.
  • The target ECS instance is faulty.
  • The network of the service provider is faulty.
  1. Log on to the Smart Access Gateway console.
  2. Click the ID of the target Smart Access Gateway instance and check whether the device is in the Ready state.
    • If the device is offline, see The SAG is offline for troubleshooting.
    • If the device is ready, proceed to 3.
  3. Log on to the switch console to check the connectivity between the device and the switch.
    • If access is provided through static routes, ping the IP address of each interface on the SAG from the switch. If you cannot ping an interface, see Link failure between SAG-1000 and the switch to restore the connection to the interface.
    • If the SAG is stand-alone, check whether the second or third indicator on the right is lit or flashing.
      • If the second indicator is lit yellow or flashing, the SAG has a software fault. Open a ticket for technical support.
      • If the third indicator is lit yellow or flashing, the VPN tunnel between the SAG and Alibaba Cloud is unavailable. Open a ticket for technical support.
      • If both the second and the third indicators are lit green, proceed to 4.

      For more information, see SAG indicators.

  4. Check the status of the ECS instance. Ping other VPC ECS instances or configure an EIP for the target ECS instance to check the connectivity by using the Internet.
    • If you can ping other ECS instances, the target ECS instance is faulty. Resolve the fault.
    • If you cannot ping other ECS instances, proceed to 5.
  5. Ping other websites from the PC. If the ping action fails, check whether the network of the service provider is normal.