Public Load Balancer - Not able to take RDP for a VM

Sivajanani Krishnamoorthy 0 Reputation points
2023-04-25T15:26:28.9433333+00:00

Hello All,

I have created a windows VM which does not have Public IP. And have created Load Balancer which assigned a Public IP for that VM. But I have problem taking RDP to the VM using Load Balancers Public IP. Here are the steps I have followed:

  1. Created VM which allows TCP 3389 and TCP 80 from specific source set and destination: any.User's image
  2. Created Load balancer with Front end IP configuration, Backend pool to access the VM, Health probe set to access port TCP 80 as follows.User's image
  3. I have created inbound NAT rules with frontend and backend port as 3389 as given in the image below.User's image

I tried taking RDP from my local machine (Not sure if there is any other option to take RDP using Load balancer public IP) But still when I try taking RDP using Load balancers public IP and port 3389 I am not able to connect to the machine although I made sure my VM is running.User's image

I have given different port ranges in Load balancer and NAT rules as I am not able to use same set of rules for both. Hence I request you to guide me if I have missed any steps or configured anything wrong.

Azure Load Balancer
Azure Load Balancer
An Azure service that delivers high availability and network performance to applications.
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  1. ChaitanyaNaykodi-MSFT 26,101 Reputation points Microsoft Employee
    2023-04-26T23:29:22.2+00:00

    @Sivajanani Krishnamoorthy

    Thank you for posting a detailed question here.

    I tried a similar set-up at my end and was able to RDP into my VM using my Public Load Balancers IP.

    User's image

    You can try validation steps below to see if everything is set-up correctly.

    • Can you please validate in the inbound NSG rule, the source IP is your local machine's public IP address? In Azure Load Balancer a response to an inbound flow is always a response from a virtual machine. When the flow arrives on the virtual machine, the original source IP address is also preserved. More information can be found here.

    User's image

    • Can you please validate if the on the VM's overview page the public IP configuration is showing the correct value (the IP listed should be Load Balancer's public IP)? If this value is not correct then there will issue with the backend pool configuration. You can delete the current backend pool association and recreate it following this documentation.

    User's image

    • Lastly there can be other problems which can cause this issue like local machine's firewall or any other NSGs blocking this connectivity. It will help troubleshoot the issue if you can create a fresh VM (and not assign it to the Load Balancers backend pool) and assign it a Public IP address, perform RDP into that VM. If you face issues you can follow this troubleshooting guide to help resolve this issue.

    Hope this helps! Please let me know if the issue persists. Thank you!

    --

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