Portable WiFi is a type of wireless internet connection that allows users to access the internet without the need for a physical wired connection. The connection is created by a small device that connects to a cellular data network and creates a wireless hotspot. This type of connection is ideal for people who travel frequently or who don’t have access to a consistent wired internet connection.

The application layer is the highest layer of the OSI model. It is the layer closest to the user, as it provides an interface for the user to access the underlying network. The application layer is responsible for network services such as email, web browsing, file transfer, and other network services. It also provides an interface for applications to communicate with other applications, over the network.

WPA2/WPA Mixed Mode is a wireless security protocol that combines the features of the WPA (Wi-Fi Protected Access) and WPA2 (Wi-Fi Protected Access 2) standards. This mode allows for the use of older WPA-enabled devices on a WPA2-enabled network. It also enables the use of newer WPA2 devices on a WPA-enabled network. This mode provides a layer of backward compatibility for older devices, while still providing the latest encryption and authentication mechanisms for newer devices.

To stop services in Linux, you can use the command “service” or “systemctl” followed by the name of the service you want to stop. For example, to stop the Apache web server, you can use the command “service apache2 stop” or “systemctl stop apache2”. You can also use the command “systemctl disable” followed by the name of the service to disable it from starting automatically at boot time.