How to resolve port 445 is not reachable from this client?

Question

How to resolve port 445 is not reachable from this client?

MHC Neuro 0

I can map a network drive from an On-prem Windows client to an Azure file share. However, if I attempt to map a network drive using a client outside of my network, I get the diagnostic error "Port 445 is not reachable from this client" In my storage account under Networking, I have the setting "Public Access from all networks" - Enabled from all networks. Why can I only map a network drive from my network and not from other networks?

Ravi Kanth Koppala 3,391 Reputation points Microsoft Employee Moderator

2023-12-19T01:14:36.9333333+00:00
@MHC Neuro
To resolve the issue of "Port 445 is not reachable from this client" when attempting to map a network drive using a client outside of your network to an Azure file share, there are several solutions you can try:

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 3 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

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 set up a VPN to access Azure Files from Windows. (Solution 2 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

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. 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 1 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

References:

Troubleshoot Azure Files connectivity and access issues (SMB)

AI Note: This solution is generated using the Microsoft Q&A AI Assist tool.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2023-12-21T11:55:59.5066667+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2024-01-01T04:38:58.85+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2024-01-03T07:11:18.7966667+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

1 answer

Your answer

Ravi Kanth Koppala 3,391 Reputation points Microsoft Employee Moderator

2023-12-19T01:14:36.9333333+00:00

@MHC Neuro
To resolve the issue of "Port 445 is not reachable from this client" when attempting to map a network drive using a client outside of your network to an Azure file share, there are several solutions you can try:

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 3 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

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 set up a VPN to access Azure Files from Windows. (Solution 2 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

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. 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 1 from the Troubleshoot Azure Files connectivity and access issues (SMB) document)

References:

Troubleshoot Azure Files connectivity and access issues (SMB)

AI Note: This solution is generated using the Microsoft Q&A AI Assist tool.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2023-12-21T11:55:59.5066667+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2024-01-01T04:38:58.85+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Anand Prakash Yadav 7,860 Reputation points Microsoft External Staff

2024-01-03T07:11:18.7966667+00:00

MHC Neuro, just checking in to see if the below-answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

Answer 1

Hello MHC Neuro,

Thank you for posting your query here!

Please check if your firewall or ISP is blocking port 445, use the AzFileDiagnostics tool or Test-NetConnection cmdlet.

Azure Files only allows connections using SMB 3.0 (with encryption support) from outside the region or datacenter. SMB 3.0 protocol has introduced many security features including channel encryption which is very secure to use over internet. However its possible that port 445 has been blocked due to historical reasons of vulnerabilities found in lower SMB versions. In ideal case, the port should be blocked for only for SMB 1.0 traffic and SMB 1.0 should be turned off on all clients.

If you have ever been blocked using Azure Files due to your ISP's port 445, you can setup a Point to Site VPN to your Azure Files. Refer to the suggestions mentioned in the GitHub article

You can mount the file share on your local machine by using the SMB 3.0 protocol, or you can use tools like Storage Explorer to access files in your file share. From your application, you can use storage client libraries, REST APIs, PowerShell, or Azure CLI to access your files in the Azure file share.

You can use Azure File Sync to access your Azure file share. https://learn.microsoft.com/en-us/azure/storage/file-sync/file-sync-deployment-guide?tabs=azure-portal%2Cproactive-portal

Please let us know if you have any further queries. I’m happy to assist you further.

Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

Share via

How to resolve port 445 is not reachable from this client?

1 answer

Your answer