Set up multicast for Windows Server in Amazon VPC Transit Gateways

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Set up multicast for Windows Server in Amazon VPC Transit Gateways - Amazon VPC

You'll need to perform additional steps when setting up multicast to work with transit gateways on Windows Server 2019 or 2022. To set this up you'll need to use PowerShell, and run the following commands:

To set up multicast for Windows Server using PowerShell

Change Windows Server to use IGMPv2 instead of IGMPv3 for the TCP/IP stack:

PS C:\> New-ItemProperty -Path HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters -Name IGMPVersion -PropertyType DWord -Value 3

Note
New-ItemProperty is a property index that specifies the IGMP version. Because IGMP v2 is the supported version for multicast, the property Value must be 3. Instead of editing the Windows registry you can run the following command to set the IGMP version to 2.:
Set-NetIPv4Protocol -IGMPVersion Version2
Windows Firewall drops most UDP traffic by default. You'll first need to check which connection profile is being used for multicast:
```
PS C:\> Get-NetConnectionProfile | Select-Object NetworkCategory

NetworkCategory
---------------
         Public
```
Update the connection profile from the previous step to allow access to the required UDP port(s):

PS C:\> Set-NetFirewallProfile -Profile Public -Enabled False
Reboot the EC2 instance.
Test your multicast application to ensure traffic is flowing as expected.