Server Migration Center:What do I do if I receive an S11 error code indicating an error in the network connection to the intermediate service of the destination instance?

Problem description

During an SMC migration job, the "S11_* An error occurred in the network connection of the intermediate service for the destination instance." error message is reported. The following S11_* error codes may be reported:

• S11_U28

• S11_U7

• S11_U56

• S11_U6

Cause

An error may occur in the network connection between the SMC client of the source server and the intermediate service of the destination instance due to one of the following causes:

• An exception occurs on port 8080 that is used by the intermediate service of the destination instance.

• The source server cannot access the IP address of the destination instance by using port 8080.

Solution

1. Check whether the intermediate service of the destination instance is normal.

   1. Log on to the ECS console.

   2. In the left-side navigation pane, choose Instances & Images > Instances.

   3. In the top navigation bar, select the region of the ECS instance.

   4. Check whether the destination instance is running as expected.

      • If the destination instance is running, perform the operations in Step e.

      • If the destination instance is stopped, start the instance and perform the operations in Step e.

      • If the destination instance is released, create another migration job. For more information, see the topics under Step 2: Create and start a migration task.

   5. Find the destination instance and click its ID. On the page that appears, click the Remote Commands/Files tab. Then, click Send Remote Commands.

      • If the source server runs a Windows operating system, enter netstat -ano | findstr 8080 in the Command Content section, then click Run.

      • If the source server runs a Linux operating system, enter netstat -ano | grep 8080 in the Command Content section, then click Run.

      If the command is executed and the information about port 8080 is returned in the Command Output section, the intermediate service of the destination instance is normal.

   6. Check whether port 8080 is enabled in the inbound rules of the security group of the destination instance or whether security group rules are conflicted.

      Note

      By default, SMC associates the destination instance with a temporary security group during a server migration and enables port 8080 in the inbound rules of the security group.

   7. Use a server other than the source server to access http://<IP address of the destination instance>:8080 to check whether the network connection is established.

      • If the server runs a Linux operating system, run the curl http://<IP address of the destination instance>:8080 command.

      • If the server runs a Windows operating system, use a browser to access http://<IP address of the destination instance>:8080.

      If normal content in the JSON format such as {"code":-101,"message":"smc p2vs get ok."} is returned, the network connection is established.

      Note

      By default, the public IP address of the destination instance is used. If you migrate data over a virtual private cloud (VPC), the private IP address of the destination instance is used.

2. Check whether the network service of the source server is normal.

   1. Check whether the local network service of the source server is normal and whether the configurations such as the hosts file and Domain Name System (DNS) settings are valid.

   2. By default, SMC migrates data over the Internet. Make sure that the source server can access the Internet.

   3. If you migrate data over a VPC, make sure that the source server is connected to the specified VPC and vSwitch. For more information, see Migrate servers over a VPC.

      Note

      If you are not sure whether the source server is connected to the specified VPC and vSwitch, we recommend that you set the Network Type parameter to Public Network when you create a migration job. If you set the Network Type parameter to VPC and the migration job fails, change the value of the Network Type parameter to Public Network and try again.

3. Check whether the network between the source server and destination instance is connected.

   1. Enable Internet Control Message Protocol (ICMP) in the inbound rules of the security group of the destination instance. Then, run the ping command to check whether the network between the source server and destination instance is connected.

      If the network is disconnected, check the local network configurations or intermediate network devices. For example, check whether the IP address of the SMC endpoint is blocked by the firewall or whether the proxy server forbids outbound traffic to the IP address of the SMC endpoint.

   2. Access http://<IP address of the destination instance>:8080 to check whether the source server is connected to the destination instance by using port 8080.

      • If the source server runs a Linux operating system, run the curl http://<IP address of the destination instance>:8080 command.

      • If the source server runs a Windows operating system, use a browser to access http://<IP address of the destination instance>:8080.

      If normal content in the JSON format such as {"code":-101,"message":"smc p2vs get ok."} is returned, the connection is established. Otherwise, check the local network configurations or intermediate network devices. For example, check whether the IP address and port of the SMC endpoint are blocked by the firewall or whether the proxy server forbids outbound traffic to the IP address and port of the SMC endpoint.

   3. Check whether Alibaba Cloud Cloud Firewall is enabled and whether access control policies are configured to block network access, such as Internet firewall and VPC firewall. For more information, see Firewall Settings.

4. After the error is resolved, run the SMC client and retry the migration job. For more information, see Run the SMC client.