Microsoft Teams Location Based Bandwidth Control (Network Roaming Policy)

Microsoft Teams now has the ability to limit the network bandwidth used by calls/meetings based on the network location of the user. This uses a feature called Network Roaming Policy. I have found the documentation relating to this feature to be a bit lacking from Microsoft, so I’ve put together this post to go into some more detail about how the policy works.

This feature is an extension of the existing Meeting Policy settings that have always been available for Teams. I wrote an extensive post about how Meeting Policy bandwidth control works  over at this post (https://www.myteamslab.com/2019/10/microsoft-teams-bandwidth-usage-deep.html). The Network Roaming policy has the same effect on the Teams client. However, it's now dynamically implemented by the client based on its location, rather than it always being on in the previous Meeting Policy implementation. This means that if you have a specific site that you know has low bandwidth constraints, then you can limit the maximum bandwidth per call and also restrict video usage for this site location only.

 

How Does the Policy Work?

The Network Roaming Policy is based on network IP Addressing of the client machine and the NATed IP Address of the client as it access the Internet. This relies on the configuration of both the Trusted IP Address ranges and Network Site subnets within the Teams Admin Centre. The client will compare both its local subnet and its public IP address (NATed address that it accesses the Internet through, e.g. Type “What's my IP” into Google) in order to know if it will implement the Network Roaming policy. The diagram below shows two different sites with different LAN Address ranges as well as different internet egress IP Addresses through the Internet facing firewall:

Note: The policy is not just based on the IP Address of the user because you could have multiple sites with the same internal private IP Address range. The Trusted IP (Public IP) must also match for the policy to be implemented by the client.

In the configuration example we will configure a Network Roaming policy for the "Low Bandwidth Site" on the left hand side of the diagram. The site on the right hand side will not be configured and will fall back to having the default bandwidth settings used for Teams.

Importantly, the only clients that currently support the Network Roaming policy at the moment are the Windows and MacOS desktop clients. So don’t expect this to work with Teams Phones, MTRs, or Linux clients. 

 

Configuration of Network Roaming Bandwidth Policy

Note: In classic cloud style, you will usually need to wait about 24 hours before this policy takes effect. As a result, make sure you're not in any kind of rush when setting this up.

Network Roaming Policy is configured under the Locations > Network Topology section of the Teams Admin Centre: 

The Network Topology section consists of 3 tabs - Network Sites, Trusted Sites and Roaming Policy. You will need to configure all of these areas in order for Network Roaming Policy to work.  For this example we will configure a policy that will limit the Teams client to only use a maximum of 300kbps worth of bandwidth for its Audio and Video streams.

Step 1. Start by creating a Network Roaming Policy from the Roaming Policy tab, select Add:

Step 2. Configure the policy with the required bandwidth per call and whether or not video will be supported (for more details about how much bandwidth is used for video calls, see my previous post here: https://www.myteamslab.com/2019/10/microsoft-teams-bandwidth-usage-deep.html):

Step 3. Select the Trusted IPs tab and click the Add button:

Step 4. The trusted IP Address is the external facing NATed IP address that Office 365 will see as the source address coming from your client connection. If you search for “What's my IP” on Google from the location it will tell you what this IP Address is. In the case of connecting to Office 365 there are likely a range of IP Addresses used here, so you need to get the Network Mask correct.  

 Step 5. In the network sites tab you need to create a new site, click the Add button:

 In the new Site policy you select the Network Roaming Policy that was created in Step 1:

Each subnet that is used internally at the site should be added to the Site by clicking the Add Subnets button:

Step 6: In addition to the Network Location configuration above, you also need to turn on Network Configuration Lookup in Meeting Policy:

Within the Meeting policy you need to ensure that the following setting is enabled:

The Microsoft Docs (https://learn.microsoft.com/en-us/microsoftteams/network-roaming-policy) say the following:

“To enable the network roaming policy for users who are not enterprise voice enabled, you must also enable the AllowNetworkConfigurationSettingsLookup setting in TeamsMeetingPolicy. This setting is off by default.”

So really, it’s best that you always turn this on if you want the Network Roaming Policy to take effect for everyone.

 

 

How do you know if the policy is working?

 

The client doesn’t display anything to the user to inform them that this policy is in use. The only way you can really tell is by looking into the Teams Client logs. You can get the client to output the logs by pressing the Ctrl + Alt + Shift + 1 keys on your keyboard. When this is done the client will output log files to your Downloads folder. From here you open up the following file:

Downloads\MSTeams Diagnostics Log <Date>\web\ MSTeams Diagnostics Log <Date>_calling.txt

This file contains information about if the client has matched any of the existing policies.

 

When the policy is not being applied you will find something like this indicating that the default policy is in use:

" networkRoamingPolicy": {

" allowIPVideo " : true ,

"mediaBitRateKb" : 50000,

"policyDocument ": "Default "

 

When the Network Roaming policy has been successfully deployed you should see the Network Roaming Policy section of the file display information about the policy that the client is implementing.  Importantly, the trustedIpMatchInfo and siteMatchInfo sections must say that they have "Matched" one of the policies.

 

Current MT location response:

{

  "emergencyCallingPolicy": {

    "policyDocument": "Default"

  },

  "emergencyCallRoutingPolicy": {

    "emergencyNumbers": [],

    "policyDocument": "Default"

  },

  "networkRoamingPolicy": {

    "allowIPVideo": true,

    "mediaBitRateKb": 300,

    "policyDocument": "TeamsNetworkRoamingPolicy=Tenant:300kbps"

  },

  "endpointNetwork": "Trusted",

  "networkSiteId": "Low Bandwidth Site",

  "enableLocationBasedRouting": false,

  "siteAddress": "Low Bandwidth Site",

  "subnetId": "10.1.0.0",

  "debugInfo": {

    "ncsDebugInfo": {

      "trustedIpMatchInfo": {

        "publicIp": "50.1.2.100",

        "trustedIpAddress": "50.1.2.100",

        "maskBits": 24,

        "reason": "Matched",

        "_comment": "Match Client Public IP to Tenant Trusted IP"

      },

      "siteMatchInfo": {

        "ipv4": "10.1.0.180",

        "subnetLengthIPv4": "24",

        "subnetId": "10.1.0.0",

        "maskBits": 24,

        "networkSiteId": "Low Bandwidth Site",

        "enableLocationBasedRouting": false,

        "reason": "Matched",

        "_comment": "Used to match endpoint subnet to Tenant site if trustedIpMatchInfo matches"

      },

      "networkLocationMatchInfo": {

        "bssid": "74-ac-b9-2e-f3-b3",

        "ipv4": "10.1.0.180",

        "reason": "NotMatched",

        "_comment": "Used to find emergency address,against Tenant Location Network Information (LIS), otherwise against Client Geo Location Information (CLS) if available"

      }

    },

    "mtDebugInfo": {

      "isDirectRoutingOnlyUser": true,

      "emergencyCallingPolicyTag": "Default",

      "emergencyCallRoutingPolicyTag": "Default",

      "networkRoamingPolicyTag": "TeamsNetworkRoamingPolicy=Tenant:300kbps",

      "emergencyCallingPolicyAssignedTo": "Tenant or Host Global",

      "emergencyCallRoutingPolicyAssignedTo": "Tenant or Host Global",

      "networkRoamingPolicyAssignedTo": "Network Site",

      "ncsResponseReceived": true,

      "correlationId": "1DEF3C2C47D64C1EB7060657876ECE95"

    }

  }

}

   

The Wrap Up

Awesome - now you can walk up to random people on the street and tell them about how you know all about Teams Network Roaming Policy. Believe me, they will be thrilled to hear all the details. Especially the bit about the AllowNetworkConfigurationSettingsLookup setting. That one really cracks them up. Cheers, Enjoy!

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Teams PowerShell Module - Certificate Authentication

There are several ways to get the Teams PowerShell module to authenticate against Azure in order to get access to running Teams PowerShell in your Tenancy. Most people will be used to using the interactive method, where you just run the basic Connect-MicrosoftTeams command and get an interactive Azure auth screen that pops up and you enter your user account details into. This is fine if you are manually connecting and doing this by hand. However, what if you want to run an Azure Function that needs to authenticate automatically each time it executes? Well, for that you want to use an application authentication method.

Currently as of the module version 4.9.1, Microsoft officially supports two methods for application authentication when connecting to the Teams PowerShell module:

• Certificate based authentication – In this method you have a certificate with private and public keys. The PC connecting to Azure needs to have a copy of the private key and Azure needs to have a stored copy of the public key. As part of the connection the private key will be used to sign the connection and if Azure can decrypt the information with the public key then the PC is trusted to connect. This essentially makes the private key like a password that you need to ensure that no one else has access to.
• Token based authentication – The token-based method requires that you set up a Client Secret in Azure. When you connect to Azure using the PowerShell module, you authenticate against the Token Service using the Client Secret and get Tokens back that you can use to connect to the service. In the case of the Teams module, you need to get two tokens to be able to run all the commands. You can find out more about this option here: Token Auth Post

In this post we are going to focus on the certificate-based authentication method. Here are the steps for setting up and connecting using certificate-based authentication:

 

Step 1: Generate a Certificate:

The good news here is that the certificate you need does not need to be signed by an internet-based Certificate Authority. You can simply create a self-signed certificate on a PC and use this for connection. Below is a PowerShell command you can run (you must run the PowerShell window as Administrator to execute it). The most important flag in the command is the KeySpec flag which tells it to generate a certificate that can be used for Key Exchange.

New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -Subject TeamsAppTestCertificate01 -KeySpec KeyExchange

 

Step 2: Export the Certificate:

In order to export the certificate you can either run PowerShell or do it by hand with the Certificate Snap-in. Both options will be detailed below. Choose the one that you’re most comfortable with.

Export the Private Key (This step is only needed if you want to run PowerShell from a different machine that you have created the certificate on, for example, a Function App, etc):

PowerShell:

$password = ConvertTo-SecureString -String "SpecialPassword123!" -Force –AsPlainText

Export-PfxCertificate -Cert "cert:\LocalMachine\My\8E4CKSHDUSG873F66D99AC7935F53" -FilePath "C:\temp\AuthPrivateKey.pfx" -Password $password

Note: The thumbprint to be used here will be output from the New-SelfSignedCertificate command you previously ran.

 

Or Windows UI:

Once again, this is is only needed if you want to run PowerShell from a different machine that you have created the certificate on, for example, a Function App, etc.

Search PC for mmc.exe > File Menu > Add or Remove Snap-in > Certificates > Add > Computer Account > Personal > Certificates Folder > Right Click on the Certificate > Export…

Export Certificate Wizard:

Click Next...

Select: "Yes, export the private key":

Go with the default export options:

Enter a password for the PFX file and ensure that you select TripleDES-SHA1 (I have found that importing on some platforms is not supported with AES):

Enter a name and location for the pfx file to be output to:

Export the Public Key (to be uploaded to the App Registration in Azure)

PowerShell:

Export-Certificate -Cert "Cert:\LocalMachine\My\8E4CKSHDUSG873F66D99AC7935F53" -FilePath "C:\temp\AuthPublicKey.cer"

Or Windows UI:

Click Next... 

Do not export private key:

Select the format of the file (DER is okay in this case) and click next:

Select the name of the file and click next:

Step 3: Configure the App Registration:

Open the Azure AD Portal and select the Azure Active Directory > App Registration section:

 Click the "New Registration" Button:

 

Fill in a name for the application and click the Register button:

The App Registration will now be created, however, there is still more config to do:

Go to the “Certificates & secrets” blade:

Select the location of the public key certificate that you exported earlier. Add a description and click OK:

The certificate should now show up in the certificates area:

Now open the API Permissions tab within the App Registration, Click "Add a permission":

You will need to add the following Graph API permissions to the App Registration:

User.Read.All

Group.ReadWrite.All

AppCatalog.ReadWrite.All

TeamSettings.ReadWrite.All

Channel.Delete.All

ChannelSettings.ReadWrite.All

ChannelMember.ReadWrite.All

These permissions are documented by Microsoft here, so you may want to check to see if there have been any updates for the PowerShell version you're using: https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-application-authentication

Click the "Microsoft Graph" option:

Select "Application Permissions":

Select the permissions that were listed above:

Ensure that you have added all the permissions. If you missed any then repeat the above steps for all the permissions in the list…

 

After adding all the permissions, you need to click the “Grant admin consent for <tenant id>” button on the main Permissions screen:

At the end of this procedure, you should have the following permissions all assigned with admin consent granted:

In a final twist in this adventure, you also need to make sure you assign Teams Administrator privileges to the App Registration in order for it to be able to run CS commands. You do this by going to the Active Directory tab > Roles and Administrators > Teams Administrator Role:

 

Assign the Service Permission that is named the same as your App Registration to the RBAC Role:

Connecting To Teams PowerShell

 

Now that all the backend work has been done we can get down to doing some connecting. When you connect it needs to be from a machine that has access to the certificate. On a PC this means it has to be in the certificate store. If it’s from a machine in Azure there are various methods for doing this too (which I may well get to in another post…).

You will need to know the ApplicationId that was given to the App Registration in Azure. You can find this out by looking going to the Overview tab and looking for the GUID that has the title “Application (client) ID”. The TenantId is the base domain name that was first given to your tenancy when it was created or alternatively can be the GUID that’s in the Overview tab named as “Directory (tenant) ID” (both options will work).

 

Teams Module Connect Command:

Connect-MicrosoftTeams -CertificateThumbprint "3ab0e057bc3278ecb2a33123042e5a7a8001ff8c" -ApplicationId "319d0a47-9a48-45b0-b416-14aca00e7ece" -TenantId contoso.onmicrosoft.com

 

When connection is successful, you’ll get back an object displayed in the PowerShell window that tells you the Account, Environment, Tenant and TenantId values. From here you should be able to run almost all of the commands from the module, with the following exclusions:

As of 4.9.1; All cmdlets are supported now, except for the cmdlets mentioned below:

• New-Team
• [Get|Set|New|Sync]-CsOnlineApplicationInstance
• *-CsUserCallingSettings
• *-CsUserCallingDelegate
• *PolicyPackage*
• *-CsTeamsShiftsConnection*
• *-CsBatchTeamsDeployment*

  

The Wrap Up

 

Congratulations, you’re now an expert at certificate-based authentication with the Teams PowerShell module. If you are interested in Token Based Authentication using the Teams Module, then you can check out my post on that over here: Token Auth Post.

Read more →

Teams PowerShell Module – Token Authentication

There are several ways to get the Teams PowerShell module to authenticate against Azure in order to get access to running Teams PowerShell in your Tenancy. Most people will be used to using the interactive method where you just run the basic Connect-MicrosoftTeams command and get an interactive Azure auth screen that pops up and you enter your user account details into. This is fine if you are manually connecting and doing this by hand. However, what if you want to run an Azure Function that needs to authenticate automatically each time it executes? Well, for that you want to use an application authentication method.

Currently as of the module version 4.9.1, Microsoft officially supports two methods for application authentication when connecting to the Teams PowerShell module:

• Token based authentication – The token-based method requires that you set up a Client Secret in Azure. When you connect to Azure using the PowerShell module, you authenticate against the Token Service using the Client Secret and get Tokens back that you can use to connect to the service. We will dig further into this method in this post.
• Certificate based authentication – In this method you have a certificate with private and public keys. The PC connecting to Azure needs to have a copy of the private key and Azure needs to have a stored copy of the public key. As part of the connection, the private key will be used to sign the connection and if Azure can decrypt the information with the public key, then the PC is trusted to connect. This essentially makes the private key like a password that you need to ensure that no one else has access to. If you would like to know more about this method, please check out my post here about it: Certificate Auth Post.

In this post we are going to focus on the token-based authentication method. Here are the steps for setting up and connecting using token-based authentication:

 

Step 1: Configure the App Registration:

Open the Azure AD Portal and select the Azure Active Directory > App Registration section:

 

Click the New Registration Button:

 

Fill in a name for the application and click the Register button:

 The App Registration will now be created. However, there is still more config to do:

Go to the “Certificates & secrets” blade:

Enter a name for your client secret that makes sense for you and click "Add":

You will now seen your new Client Secret. Copy the secret value and put it somewhere safe:

I'll say it again, before leaving this screen take a copy of the Client Secret Value because it will not be available when you return later. Also, it’s important that you treat this secret as you would a password because it can give anyone the keys to your Teams castle… which would be very bad.

 

Configure the Application Permissions:

You will need to add the following Graph API permissions to the App Registration:

User.Read.All

Group.ReadWrite.All

AppCatalog.ReadWrite.All

TeamSettings.ReadWrite.All

Channel.Delete.All

ChannelSettings.ReadWrite.All

ChannelMember.ReadWrite.All

These permissions are documented by Microsoft here, so you may want to check to see if there have been any updates for the PowerShell version you're using: https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-application-authentication

 

Click the "Microsoft Graph" option:

Select "Application Permissions":

Select the permissions that were listed above:

Ensure that you have added all the permissions. If you missed any then repeat the above steps for all the permissions in the list…

 

After adding all the permissions you need to click the “Grant admin consent for <tenant id>” button on the main Permissions screen:

At the end of this procedure you should have the following permissions all assigned with admin consent granted:

 

In a final twist in this adventure, you also need to make sure you assign Teams Administrator privileges to the App Registration in order for it to be able to run CS commands. You do this by going to the Active Directory tab > Roles and Administrators > Teams Administrator Role:

 

Assign the Service Permission that is named the same as your App Registration to the RBAC Role:

 

Connecting To Teams PowerShell

 

Now that all the backend work has been done, we can get down to doing some connecting.

You will need to know the ApplicationId that was given to the App Registration in Azure. You can find this out by looking going to the Overview tab and looking for the GUID that has the title “Application (client) ID”. The TenantId is the base domain name that was first given to your tenancy when it was created or alternatively can be the GUID that’s in the Overview tab named as “Directory (tenant) ID” (both options will work). And you need to know the Client Secret that was created at the beginning of the App Registration creation process (I did tell you to take note of this -- if you didn’t then you may not be able to see the secret in the portal anymore. If so, then you need to create a new one).

  

The Connection PowerShell:

$ClientSecret   = "P_1a3~cNhA1Jd~iS9.mdUh2ffe_qp~u9Leuk4aYa" # Your Client Secret

$ApplicationID = "00000000-0000-0000-0000-000000000000" #Your Application ID

$TenantID = "YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYYY" #Your Tenant ID

 

$graphtokenBody = @{  

   Grant_Type    = "client_credentials"  

   Scope         = "https://graph.microsoft.com/.default"  

   Client_Id     = $ApplicationID  

   Client_Secret = $ClientSecret  

} 

 

$graphToken = Invoke-RestMethod -Uri "https://login.microsoftonline.com/$TenantID/oauth2/v2.0/token" -Method POST -Body $graphtokenBody | Select-Object -ExpandProperty Access_Token

 

$teamstokenBody = @{  

   Grant_Type    = "client_credentials"  

   Scope         = "48ac35b8-9aa8-4d74-927d-1f4a14a0b239/.default"

   Client_Id     = $ApplicationID  

   Client_Secret = $ClientSecret

}

 

$teamsToken = Invoke-RestMethod -Uri "https://login.microsoftonline.com/$TenantID/oauth2/v2.0/token" -Method POST -Body $teamstokenBody | Select-Object -ExpandProperty Access_Token

 

Connect-MicrosoftTeams -AccessTokens @("$graphToken", "$teamsToken")

 

I know what you’re thinking… That’s a lot of PowerShell code to just connect to PowerShell and you are correct in thinking that. However, this code, while looking ominous, is actually not all that complicated when you break it down.

Let’s break it down; The first 3 lines are variables where you need to fill in your specific Secret, Application ID and Tenant ID. These are the only three lines that you need to edit, so you can relax. The other lines of code basically run two separate REST calls to Azure to get access to two different tokens. One token is for the Graph API and the other is for Teams. Once you have these tokens you then pass them to the Connect-MicrosoftTeams command which uses them to authenticate against the service.

Note: The tokens have a lifetime of 1 hour, so if you were going to make an app that was going to make a lot of connections over the course of an hour you make want to cache the tokens and reuse them.

When connection is successful, you’ll get back an object displayed in the PowerShell window that tells you the Account, Environment, Tenant and TenantId values. From here you should be able to run almost all of the commands from the module, with the following exclusions:

As of 4.9.1; All cmdlets are supported now, except for the cmdlets mentioned below:

• New-Team
• [Get|Set|New|Sync]-CsOnlineApplicationInstance
• *-CsUserCallingSettings
• *-CsUserCallingDelegate
• *PolicyPackage*
• *-CsTeamsShiftsConnection*
• *-CsBatchTeamsDeployment*

The Wrap Up

 

There’s all you should hopefully need to know about setting up a simple Token Authentication based connect to Microsoft Teams PowerShell. At the beginning of the post I also mentioned Certificate-based authentication. If you would like to know more about Certificate-based authentication, don’t forget you can check out my post here about it: Certificate Auth Post.

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