Which subnet should be added to enable network communication interoperability

Question

I want to use azcopy to transfer files from storage account A to storage account B. Where storage account A is in subnet a, and storage account B in subnet b, Azcopy is deployed in VM, which is in subnet c. What confuses me is when adding a network through Azure portal:

1. Is it enough to add subnet c of VM to storage account B?
2. Do need to add both subnet a and subnet c to storage account B ? Should I choose 1 or 2?

Answer 1

By default Azure creates routes between all the subnets in VNet. See https://learn.microsoft.com/en-us/azure/virtual-network/tutorial-create-route-table-portal

so as long as all those objects are within the same Vnet, you don't need to add anything.

Answer 2

Hi @Huang, Winston-HR You should add subnet C (where your VM is deployed) to the network rules of storage account B. This ensures that the VM can communicate with storage account B. You will also need to ensure that the VM has appropriate access to storage account A, but this does not require adding subnet A to the network rules of storage account B. Instead, you should verify that your VM's subnet (subnet C) has the necessary permissions and routes to access storage account A, which can be configured via network security groups (NSGs), service endpoints, or private links for enhanced security. In summary, focus on configuring network access for the VM in subnet C to both storage accounts individually, rather than trying to link subnet A and subnet B directly for the purpose of using AzCopy.

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Answer 3

@Huang, Winston-HR Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

The simple, across the board rule, is that AzCopy must be able to talk to both the source and the destination, and the destination must be able to talk to the source.

• AzCopy talks to the source to find out what files to copy.
• AzCopy then talks to the destination, and instructs it to copy the files.
• The destination then talks to the source, and attempts to get the files in question.

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

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