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Tunnel connected but unable to connect to RDP or ping virtual machine

Isabella R. Rivera 0 Reputation points
2025-03-26T16:01:07.55+00:00

We have successfully established a site-to-site VPN connection, and the tunnel shows as connected. However, we are unable to connect to the virtual machine via RDP or ping. We've configured our SonicWall firewall, which is receiving packets, but Azure is not sending any replies back. We've confirmed that the issue is not with the SonicWall configuration. On the Azure side, we have created both the gateway subnet and the virtual network gateway. Despite the tunnel being up, there is no response from Azure, and connectivity to the VM remains unavailable.

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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  1. Rohith Vinnakota 3,835 Reputation points Microsoft External Staff
    2025-03-26T17:42:21.0633333+00:00

    Hi @Isabella R. Rivera

    • Ensure that the NSG associated with the VM's subnet or NIC allows inbound RDP (port 3389) and ICMP (ping) traffic.
    • Check for any UDRs applied to the subnet that might be misrouting traffic.
    • Ensure traffic destined for the on-premises network is routed through the virtual network gateway.
    • Confirm the IP address range of your on-premises network is correctly defined in the Local Network Gateway in Azure.
    • Ensure the Azure VPN gateway's IP is correctly configured on the SonicWall device.
    • Use the Effective Routes feature in the Azure portal to verify the routing table for the VM's subnet. Ensure routes for the on-premises network are correctly configured.
    • Check the Windows Firewall (or any other firewall) on the VM to ensure it allows RDP and ICMP traffic.
    • If there is any Azure Firewall between your Spoke VNets and VPN gateway, make sure you allow traffic between the networks.
    • Use the Network Watcher tool in Azure to test connectivity from the VM to the on-premises network and vice versa. This can help pinpoint where the traffic is blocked.
      https://learn.microsoft.com/en-us/azure/network-watcher/connection-troubleshoot-manage?tabs=portal
    • If the issue persists, try resetting the Azure VPN gateway to resolve any transient issues with the gateway.
    • Can you check the VPN diagnostic logs.

    Refer this doc :https://learn.microsoft.com/en-us/azure/vpn-gateway/troubleshoot-vpn-with-azure-diagnostics

    Kindly let us know if the above helps or you need further assistance on this issue.

    Please do consider to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

    1 person found this answer helpful.

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