Azure File Sync TCP/DNS errors

Question

Hi folks

Having an issue with a pre-existing Azure File Sync. It used to work, and stopped a couple months ago. This is a private server.

When I run a netconnect to port 443, it fails but ping succeeds. Even after opening all traffic to that port on the server. When I run a test-storagesyncnetworkconnectivity, it gives me a DNS name does not exist error. I cannot find any information on how to set up DNS records for it, but it also didn't have any before and worked?

I've blown it away and reconnected it (I know it says you're not supposed to but I've tried many other options before as well) and still nothing.

Any help on this would be appreciated, thank you,

Answer 1

Hello Nick,

Greetings! Welcome to Microsoft Q&A platform.

I understand that you’re facing issues with your Azure File Sync setup. Ensure that your server can resolve DNS names. If you encounter a “DNS name does not exist” error, consider the following

Check "Client for Microsoft Networks" is updated on NIC property protocol and installed and restart the machine. Try if you able to join.

Please check the Server’s configured IP address settings too as you are encountering the DNS resolution issue while trying to execute the ‘Test-StorageSyncNetworkConnectivity’ command. In the IP address settings, please check whether the DNS server IP addresses (Preferred and Secondary) are configured correct and are reachable.

Azure File Sync uses two channels for synchronization:

• FileREST protocol: This HTTPS-based protocol accesses your Azure file share. Only outbound port 443 needs to be accessible.
• Azure File Sync sync protocol: This HTTPS-based protocol exchanges synchronization knowledge (version information, metadata, etc.). It also uses outbound port 443.
• DNS Forwarding: Configure DNS forwarding to resolve Azure-specific DNS names. You can set up conditional forwarding of *.core.windows.net (or the appropriate storage endpoint suffix) to a DNS server within your Azure virtual network. Refer to Configuring DNS with Azure Files., https://learn.microsoft.com/en-us/azure/dns/dns-operations-recordsets-portal.
• Check DNS Settings: Manually enter your company’s DNS server information on the machine, even if it uses DHCP. Confirm that the server’s time and time zone match your DNS server’s.
• Remove Unnecessary DNS Entries: Remove any extraneous DNS entries from the NIC card settings except for the primary DNS/DC.
• This error typically occurs because the server time is incorrect. If the server is running in a virtual machine, please cross verify the time on the host is correct.

Once you made any changes, restart the server and retry the Azure File Sync registration.

refer troubleshooting doc- https://learn.microsoft.com/en-us/troubleshoot/azure/azure-storage/file-sync-troubleshoot

Remember that Azure File Sync doesn’t support internet routing, and the default network routing option (Microsoft routing) is supported. If you’ve configured a private endpoint, refer to the documentation on configuring private endpoints for Azure File Sync.

Similar SO thread for reference - https://stackoverflow.com/questions/73401796/filesync-local-endpoint-offline

Hope this answer helps! Please let us know if you have any further queries. I’m happy to assist you further.

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