This topic describes how to diagnose and fix the issue where your application cannot reach a Microservices Engine (MSE) instance over the public network.
Symptoms
Connections from your application to the MSE instance fail with one of the following behaviors:
The connection times out with no response.
The connection is actively refused.
Possible causes
| Cause | Description |
|---|---|
| IP address whitelist misconfiguration | The public IP address of your application is not in the IP address whitelist of the MSE instance. |
| Changed public IP address | The public IP address of your application changed after a redeployment, scaling event, or dynamic IP reassignment. |
Diagnose and resolve the issue
Work through the following steps in order.
Step 1: Test connectivity
From the machine that runs your application, test whether the MSE instance endpoint is reachable:
telnet <mse-instance-endpoint> <port>If the connection fails, proceed to Step 2.
If the connection succeeds, the network path is open. Check your application-level configuration instead.
Step 2: Check the IP address whitelist
Log in to the MSE console.
Open the details page of your MSE instance.
Verify that the public IP address of your application is in the IP address whitelist.
If the address is missing, add it. For instructions, see Configure a public IP address whitelist.
Step 3: Verify the current public IP address
The public IP address of your application may have changed since you last updated the whitelist. Run the following command on the application host to get the current address:
curl ifconfig.meCompare the output with the addresses in the whitelist. If they do not match, update the whitelist with the new address.
Step 4: Confirm the fix
After you update the whitelist, test connectivity again:
telnet <mse-instance-endpoint> <port>A successful connection confirms that the issue is resolved.