Entrypoint refers to the identity of a site in a multisite deployment for which the IPv6 prefix needs to be configured. Entrypoint ...

Entrypoint refers to the identity of a site in a multisite deployment for which the IPv6 prefix needs to be configured. Entrypoint is not applicable to the IPv4 address assignment properties as these properties are always configured at the individual server level and not site level

If an entrypoint is not specified in a multisite deployment then the entrypoint to which the server on which the cmdlet is executed belongs is used. The server could also be represented by using the ComputerName parameter 

If both entrypoint and ComputerName are specified and the ComputerName does not belong to the site represented by the entrypoint then the entrypoint takes precedence and the authentication type is configured for it