If your environment does not include vCenter Server, clients can connect directly to the ESXi network.

You can connect to a standalone ESXi host in several ways.
  • VMware Host Client
  • ESXCLI interface
  • vSphere Web Services SDK or vSphere Automation SDKs
  • Third-party clients
The firewall requirements for standalone hosts are similar to requirements when a vCenter Server is present.
  • Use a firewall to protect your ESXi layer or, depending on your configuration, your clients, and the ESXi layer. This firewall provides basic protection for your network.
  • Licensing in this type of configuration is part of the ESXi package that you install on each of the hosts. Because licensing is resident to ESXi, a separate License Server with a firewall is not required.

You can configure firewall ports using ESXCLI or using the VMware Host Client. See vSphere Single Host Management - VMware Host Client.