No, the Meraki MX Large Essentials EA 3.0 license is tied to physical MX hardware, such as the MX105. It cannot be reused for a vMX-L deployment. The vMX appliances require their own dedicated license, typically labeled as LIC-VMX-L-ENT-xY.
Yes, you need an active Azure subscription, but no separate license from Azure is required specifically for the Meraki vMX.
vMX Setup Guide for Microsoft Azure - Cisco Meraki Documentation
The preferred mode is Routed/NAT Mode, especially for newer deployments. All new vMX instances are deployed in Routed/NAT Mode by default.
Yes, vMX-L supports NAT mode in Azure, starting from firmware MX 19.1+.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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