Merge pull request #91023 from kgremban/oct8-gatewayissues

Clarify output from gateway connection test

Author: ktoliver

articles/iot-edge/how-to-connect-downstream-device.md

@@ -4,7 +4,7 @@ description: How to configure downstream or leaf devices to connect to Azure IoT
 author: kgremban
 manager: philmea
 ms.author: kgremban
-ms.date: 09/07/2019
+ms.date: 10/08/2019
 ms.topic: conceptual
 ms.service: iot-edge
 services: iot-edge
@@ -178,18 +178,24 @@ This section introduces a sample application to connect an Azure IoT Java device
 This section introduces a sample application to connect an Azure IoT Python device client to an IoT Edge gateway. 
 
 1. Get the sample for **send_message** from the [Azure IoT device SDK for Python samples](https://github.com/Azure/azure-iot-sdk-python/tree/master/azure-iot-device/samples/advanced-edge-scenarios). 
-2. Ensure that you are either running in an Edge container, or in a debug scenario, have the `EdgeHubConnectionString` and `EdgeModuleCACertificateFile` environment variables set.
+2. Ensure that you are either running in an IoT Edge container, or in a debug scenario, have the `EdgeHubConnectionString` and `EdgeModuleCACertificateFile` environment variables set.
 3. Refer to the SDK documentation for instructions on how to run the sample on your device. 
 
 
 ## Test the gateway connection
 
-This is a sample command that tests that everything has been set up correctly. You should see a message saying "verified OK".
+Use this sample command to test that your downstream device can connect to the gateway device: 
 
 ```cmd/sh
 openssl s_client -connect mygateway.contoso.com:8883 -CAfile <CERTDIR>/certs/azure-iot-test-only.root.ca.cert.pem -showcerts
 ```
 
+This command tests connections over MQTTS (port 8883). If you're using a different protocol, adjust the command as neccessary for AMQPS (5671) or HTTPS (433).
+
+The output of this command may be long, including information about all the certificates in the chain. If your connection is successful, you'll see a line like `Verification: OK` or `Verify return code: 0 (ok)`.
+
+![Verify gateway connection](./media/how-to-connect-downstream-device/verification-ok.png)
+
 ## Troubleshoot the gateway connection
 
 If your leaf device has intermittent connection to its gateway device, try the following steps for resolution.