Restricting access to the services and ports on an ESXi host is critical to protecting against unauthorized intrusion in your vSphere environment.

If a host is compromised, the virtual machines on that host are now threatened to be compromised as well. Restrict access to services and ports, an ESXi host is protected with a firewall. Using the ESXi lockdown mode and limiting access to the ESXi Shell can further contribute to a more secure environment.