To provision a secure customer domain in a virtualized multi-tenant environment, a virtual machine (VM) is configured for a customer in the customer domain. A first, second, and third virtual network interfaces (VNICs) are configured in the VM. The first VNIC has a first network address within a first address range selected for the customer domain and enables an application on the VM to access a second application in a second VM in the customer domain. The second VNIC enables a third application outside the customer domain to access the VM in the customer domain. The second VNIC is configured to use an addressing specification used by a server of the third application. The third VNIC enables access from the first application to a fourth application executing outside the customer domain. The third VNIC is configured to use an addressing specification used by a server of the fourth application.