Configuring Communication Among ESXi, vCenter Server, and the vSphere Web Client

By default, the vSphere Web Client uses ports 80 and 443 to communicate with vCenter Server and ESXi hosts.

Configure your firewall to allow communication between the vSphere Web Client and vCenter Server by opening ports 80 and 443.

vCenter Server acts as a web service. If your environment requires the use of a web proxy, vCenter Server can be proxied like any other web service.