How to allocate a static IP address to a virtual machine?

[WJA96]

Surely the VM should sit on an internal IP address, and then on your router you port forward from the static IP to your internal IP address.

Sitting an entire server on a public static IP is bad practice - you want as little attack surface as possible.

I assumed that was what the OP wanted when they asked about a router that would handle 5 fixed IPs. The infamous Multi-WAN interface!