Retirement: Azure Load Balancer Inbound NAT rule version 1 for Azure VMSS (aka Inbound NAT Pools)

Update to our previous communication: We previously announced the retirement of all Inbound NAT rules version 1 resources, which included both single-VM NAT rules and NAT pools for Virtual Machine Scale Sets. We have narrowed the scope of this retirement to Inbound NAT pools only.

NAT pools are being retired because they provide the same functionality as Inbound NAT rules v2, which offer improved performance and is the recommended option for Virtual Machine Scale Sets (VMSS).

Understanding the difference:

Inbound NAT rules version 1 includes two resource types:

• Inbound NAT rules version 1: Port forwarding to a single virtual machine. This feature is not affected.
• Inbound NAT pools: Port forwarding to Virtual Machine Scale Set instances. This feature is retiring.

On September 30, 2027, Inbound NAT pools in Azure Load Balancer will be retired. Starting November 15, 2026, you will no longer be able to create new Inbound NAT pools. Existing configuration will continue to function until September 30, 2027.

Recommended action:

To avoid potential service disruptions, we recommend that you migrate to Inbound NAT rules version 2 in Azure Load Balancer by September 30, 2027.