How to determine why a VM in Azure can't talk to VM in on-prem network

curious7 151 Reputation points
2021-09-28T13:07:36.16+00:00

We have a VM in our Azure Vnet.
There is express route from on-premises network to Azure.
This VM can't open a https site on the on-prem server.
I added a NSG rule to allow https traffic outbound from Azure VM but the site still does not load.
I checked the routes on the NIC of this VM and it has a route to on-prem network with next hop listed as "Virtual network gateway" and source as "virtual network gateway".

I even created a new routing table with route to "Virtual network gateway" and source as "default" and attached it to the subnet for VM.
But still not working.
What else can I try and what could be the problem.

Azure Virtual Network
Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
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Windows Server
Windows Server
A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.
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Azure ExpressRoute
Azure ExpressRoute
An Azure service that provides private connections between Azure datacenters and infrastructure, either on premises or in a colocation environment.
320 questions

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  1. Limitless Technology 39,331 Reputation points
    2021-09-28T18:00:30.75+00:00

    Hi Curious 7,

    Thank you for your question.

    I recommend that you consult the articles below that will deal with the main problems of this type of connection and how to solve it:

    https://learn.microsoft.com/en-us/azure/virtual-network/troubleshoot-vm-connectivity

    https://learn.microsoft.com/en-us/microsoft-365/enterprise/connect-an-on-premises-network-to-a-microsoft-azure-virtual-network?view=o365-worldwide

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    If the answer is helpful, please vote positively and accept as an answer.

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