Q: What is the new multi-NIC capability in Azure?
A: Azure now supports virtual machines with multiple vmNICs. Each vmNIC can connect to a different virtual subnet within the same virtual network. With a virtual machine connected to multiple subnets, this enables several new scenarios, such as network virtual appliances. The number of vmNICs supported depends on the size of the virtual machine—specifically, the number of cores:
| VM Size (Standard SKUs) | NICs (max allowed) |
| Small (1 core), medium (2 cores) | 1 |
| Large (4 cores) | 2 |
| Extra large (8 cores) | 4 |
| A8/A9 | 1 |
The multiple NICs must be added at the time of the virtual machine creation and must be done through PowerShell. Note that only the default NIC can communicate via the Cloud Service VIP.
Additional NICs must be added at the time of the virtual machine creation by adding additional network interfaces via the Add-AzureNetworkInterfaceConfig cmdlet; for example:
Add-AzureNetworkInterfaceConfig -Name "Ethernet1" -SubnetName "Midtier" -StaticVNetIPAddress "10.1.1.111" -VM $vm
You also need to set the network configuration for the default NIC added as part of a standard virtual machine.
For more information, see the Microsoft article "Create a VM with Multiple NICs."
