Issues Mapping Azure Files Storage After ISP Modem Replacement

[dmned]

A few years ago, we transitioned from an on-premises server to using Azure Files Storage for managing our files. To ensure accessibility, we mapped 10–11 Azure folders to drive letters on client workstations via File Explorer. This setup worked seamlessly until yesterday when our ISP replaced our connectivity hardware.

Original Configuration:

• ISP modem (Spectrum) connected directly to a FortiGate device.
• FortiGate configured with a static IP provided by the ISP for VPN connectivity.

New Configuration:

• ISP replaced the modem with a modem-router combo (to maintain the static IP).
• Configuration: ISP modem-router → FortiGate device.

This resolved our intermittent connectivity issues and improved bandwidth. However, the new setup has caused problems with accessing Azure Files Storage.

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Issue Details:

1. Symptoms:

   • On my home network (Frontier), I can map Azure file shares on my laptop (Windows 11) as before.
   • On the office network:
     • My Windows 11 laptop cannot access the mapped Azure shares.
     • A different laptop (Windows 10) shows Azure resetting the SMB connection during mapping attempts.
     • SMB3 protocol explicitly appears in home network WireShark captures, but not in office network logs.

2. Debugging Steps Taken:

   • DNS resolution for Azure Files works on both home and office networks.
   • Port 445 is confirmed open through routing on the office network.
   • Spectrum claims the new modem-router operates as a "pass-through" device with no traffic modifications.

Despite these checks, Azure SMB connections fail in the office network. I’m looking for suggestions to diagnose and resolve this issue.

[Stephen_G]

Hello,

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible.

[dmned]

Thank you for the reply.

No solution but perhaps a few more details. I have two laptops, one I will call Home which runs Windows 11 and the other I will call Work which runs Windows 10. Neither laptop has been able to function as they have before the ISP hardware modification on the Office LAN. Prior to the modification both laptops could map to the Azure Files Storage file shares whilst on the Office LAN.

During some of my tests I used Wireshark to monitor the communication exchanges. While on the Office LAN with the Work laptop I noticed a breakdown in the SMB exchange between the laptop and AzFS instance. I presumed it was due to a deprecated SMB version being used, but this laptop was able to map to AzFS prior to the hardware modification and nothing has been changed in its SMB configuration. Unfortunately I do not have a saved Wireshark file for the testing on the Office LAN.

Initially, the Home laptop was able to map to the AzFS file shares whilst that laptop was on my Home LAN. I have the AzFS Networking set to accept any public connection while I diagnose this issue. As of two days ago, the Home laptop could still map to the file shares.

Two days ago, I also tested the Work laptop on my Home LAN and was able to map at least one file share on that laptop. Presumably I could have successfully tested all the mapped drives but did not have the time.

I have confirmed port 445 is open in all scenarios and also nslookup is able to resolve the AzFS name.

The issue seems to be with the ISP hardware, our FortiGate device, or both, but I am not sure how to proceed.

[Stephen_G]

Thanks for elaborating on what you've tested! We are still looking for someone to help you.

Have you been able to open a TAC ticket?

[sjoshi]

Hi,

To resolve the issue with accessing Azure files storage after the ISP replaced the modem with a modem-router combo, you may need to update the FortiGate device's configuration to ensure proper routing and connectivity to Azure. Check the following steps:

1. Update the FortiGate device's routing table to correctly route traffic to Azure.
2. Verify that the FortiGate device's firewall settings allow traffic to and from Azure.
3. Ensure that the FortiGate device's VPN configuration, especially for Azure connectivity, is correctly set up.
4. Double-check the mapping of Azure folders to drive letters on client workstations to ensure they are still correctly configured.

By following these steps, you should be able to address the issues with accessing Azure files storage in your new network setup.