One of the common issues when configuring Local Media Optimization is that the Teams client is not detecting that it is inside the internal network. In this article, I am explaining how to check the logs to see if the Teams Client knows that is internal.
The reason for the client not knowing that it is internal is that it doesn’t find its own Public IP in the list of Trusted IPs (the list is configured on the tenant). And that makes it behave as if it is external and not internal (when a client starts, it will detect its Public IP and compares it to the list of Trusted IPs).
Since the client thinks that it is external and not internal it will not try to connect to the internal interface of Central SBC or downstream SBC at its site for media traffic. Instead, it will try to pass the media traffic through the Public IP of the SBC of the Central SBC or Proxy SBC. Finally, when that connection is not passable, it will try to connect to Microsoft Phone System (Teams servers on the cloud).
Based on my experience, even if you have configured the Trusted IP correctly on the tenet, it takes some time for that change to be reflected on the Teams client. (Although Microsoft documentation says it requires 30 minutes or just restarting the client will make the change to be reflected)
Usually, I don’t enable Local Media Optimization on the SBC device until I am sure that the clients are detecting that they are coming from a Trusted IP by checking the logs (as explained below)
Below I am explaining how to check the logs to verify that the client is detecting that it is coming from a Trusted IP.
Downloading the Logs
To download the logs of Teams Client, click on the keys Ctrl + Alt + Shift + 1 together while Teams client is in focus
On the right side of the screen, you will see some messages that indicate that the downloading started
Opening the log file
To access the log files, open the “Downloads” folder on the computer
Inside it, you see a folder that started with MSTeams Diagnostics Log [Date]__[Time]_
Inside it, you will find a folder named “web”. Open the “web” folder
You will find some logs files, open the file that ends with the word “calling” the file name will be in the format MSTeams Diagnostics Log [Date]__[Time]_calling.txt
Checking The Contents of The Log File
This is how the file would appear
The log file shows Public IP detected doesn’t match any Trusted IP
The following is the log file section that shows that the client’s public IP is detected and it also shows that this IP doesn’t match any of the IPs of the trusted IP list (“reason”: “NotMatched”)
The log file shows that Public IP is matching a Trusted IP
The log file is showing public IP is matching the Trusted IP (“reason”: “Matched“) and it also shows the detected Network Site. With this, we are sure that the client detected that it is internal, and it is ready to utilize your Local Media Optimization settings
