ER Direct with FastPath on GW connection and UDRs in GW subnet

Question

In a non-VWAN hub'n'spoke setup, can I be sure that my GW Subnet UDRs are honored, even with FastPath enabled on the ER GW connection to my ER Direct Circuit?

Can I verify it in CLI somehow?

Thanks!

/Thomas Winther

Answer 1

Hi Thomas Hornbæk Winther,

We appreciate your Patience!

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

Please find the confirmation from the Azure ExpressRoute product team below:

Question: In a non-VWAN hub'n'spoke setup, can I be sure that my GW Subnet UDRs are honored, even with FastPath enabled on the ER GW connection to my ER Direct Circuit?

• Yes, your UDRs on the GW subnet with FP enabled are honored.

Refer: https://learn.microsoft.com/en-us/azure/expressroute/about-fastpath#circuits

https://techcommunity.microsoft.com/blog/azurenetworkingblog/expressroute-fastpath-for-udrs-and-vnet-peering/4171115

Question: Can I verify it in CLI somehow?

Yes, you can validate FastPath & UDRs via the route table with Azure PowerShell:

• FastPath:

Get-AzVirtualNetworkGateway -Name <GatewayName> -ResourceGroupName <ResourceGroupName> | Select-Object -ExpandProperty EnableFastPath - Command 

will return True if FP is enabled. False if it's not.

• UDR: Retrieve the route table with

$routeTable = Get-AzRouteTable -Name <RouteTableName> -ResourceGroupName <ResourceGroupName>

list the routes & check to ensure your UDR is honored/present: $routeTable.Routes

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Hope this clarifies,

Please don’t forget to close the thread by clicking "Accept the answer" wherever the information provided helps you, as this can be beneficial to other community members.

Regards,

Ganesh