If you are using VMs within the public cloud, configure these VMs to reside in the same Vnet. When configuring the software, use private IP addresses to connect to these VMs.
If you are using VMs to connect from the Azure public cloud to an on-premises Teradata system, use public IP addresses to connect to the on-premises Teradata system when configuring the software.
You need to use public IP addresses only if you deploy a VM using a public Azure virtual network. If you deploy a VM using a private Azure virtual network, the VMs have private IPs and a Vnet connection is required for SSH access.