Unable to connect to Azure File Share when traveling

Question

Thanks for your response below.

Answer 1

@Nae

If I understand correctly you are using Azure file shares and users are able to access their files when at your local office and in the same country. However, others cannot access the file share when they are not connected on these networks.

If you could share a direct error message I could diagnose this further. You could also check that error on our Troubleshooting page. Based on the information you provided I believe the issue is the SMB port 445 is being blocked by some of the ISPs. Many ISPs block SMB traffic over port 445, which can cause connectivity issues when accessing Azure file shares from different locations.

Workarounds and testing for this block can be found here, I am including the information below:

Solution 1 — Use Azure File Sync as a QUIC endpoint You can use Azure File Sync as a workaround to access Azure Files from clients that have port 445 blocked. Although Azure Files doesn't directly support SMB over QUIC, Windows Server 2022 Azure Edition does support the QUIC protocol. You can create a lightweight cache of your Azure file shares on a Windows Server 2022 Azure Edition VM using Azure File Sync. This configuration uses port 443, which is widely open outbound to support HTTPS, instead of port 445. To learn more about this option, see SMB over QUIC with Azure File Sync.

Solution 2 — Use VPN or ExpressRoute By setting up a virtual private network (VPN) or ExpressRoute from on-premises to your Azure storage account, with Azure Files exposed on your internal network using private endpoints, the traffic will go through a secure tunnel as opposed to over the internet. Follow the instructions to setup a VPN to access Azure Files from Windows.

Solution 3 — Unblock port 445 with help from your ISP/IT admin Work with your IT department or ISP to open port 445 outbound to Azure IP ranges.

Solution 4 — Use REST API-based tools like Storage Explorer or PowerShell Azure Files also supports REST in addition to SMB. REST access works over port 443 (standard tcp). There are various tools that are written using REST API that enable a rich UI experience. Storage Explorer is one of them. Download and Install Storage Explorer and connect to your file share backed by Azure Files. You can also use PowerShell that also uses REST API.

Hope this helps! Let me know if you still have questions or need further assistance.

---

If you still have questions, please let us know in the "comments" and we would be happy to help you. Comment is the fastest way of notifying the experts.

If the answer has been helpful, we appreciate hearing from you and would love to help others who may have the same question. Accepting answers helps increase visibility of this question for other members of the Microsoft Q&A community.

Thank you for helping to improve Microsoft Q&A!