I need to install vCenter server on ESXi host, but there is a constraint that- vCenter and ESXi host are required to be on different IP ranges, i.e vCenter server is on one machine and ESXi host on other.
First install the ESXi server on a physical machine, and configure the network. Then you can download the Vsphere client using the IP through browser.
You can control the ESXi host through this tool.
After this you can install VCenter server in VM or in physical machine. Then you can add this ESXi host into VCenter and manage it.
It Is not mandatory to keep both the servers is same VLAN. The VCenter server and ESXi host IP’s should ping each other that is enough.
If you need more details on implementation get back to me.