The vSphere API is hosted as a secure Web service on a vCenter Server and ESX/ESXi system.
By default, the Web service is available over HTTPS. Clients must provide valid credentials to connect to the service. Depending on the specifics of your server, you might have to enter only a user name and password. You might need other information. See Options Available for All SDK for Perl Commands.
A call to Util::connect() connects to the server.
When a script reaches the call to Util::connect(), the vSphere SDK for Perl runtime checks the environment variables, configuration file contents, and command-line entries (in this order) for connection options. If the options are not defined, the runtime uses the defaults (localhost
and no user name and password) to set up the connection.