Inconsistent API Response for Subnet IP Address: addressPrefixes vs. addressPrefix in Get Virtual Network API

Question

Hi,
We noticed the following behavior:
When using the Get Virtual Network API, sometimes the subnet IP address is returned as a list, like this:

"subnets": [ {
	"name": "AzureFirewallSubnet", 
	"id": "/subscriptions/

Answer 1

@Shaked Eyal ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

From your verbatim, I see you noticed Virtual Networks - Get REST API is returning "subnets" as a list.

• This is expected
• subnets is supposed to be a list only, see Microsoft.Network virtualNetworks ARM Template

I take it that, you are actually concerned about the "subnets.properties.addressPrefix" and "subnets.properties.addressPrefixes"

• Can you confirm
  • If this is same results with a particular Subnet
  • or even with a particular Subnet, sometimes you are getting a list and sometimes you are not
• The former is also an expected behavior
• From the "Export Template" blade of the Virtual Network - you would notice that the certain VNETs would have subnets' address range as addressPrefixes while others have addressPrefix
• This is because of the recent changes in the creation of VNET with Portal
  • Newer VNETs would use addressPrefixes
  • While older VNETs would use addressPrefix
• This also depends on how the VNET was created via Template or CLI or Powershell

In case you notice a particular Subnet sometimes returning addressPrefix and sometimes returning addressPrefixes, we can look into this.

Thanks,

Kapi

---

Please don’t forget to close the thread by clicking "Accept the answer" wherever the information provided helps you, as this can be beneficial to other community members.