Advanced Placement (AP) Computer Science

What is a private IP address used for?

1. To identify devices on an external network

2. To communicate with public servers over the internet

3. To connect devices internally within a network

4. To directly access the internet without a router

The correct answer is: To connect devices internally within a network

A private IP address is specifically designed for use within a local area network (LAN). It enables devices, such as computers, printers, and smartphones, to communicate with each other internally without being exposed to the wider internet. This is beneficial for maintaining security and privacy within local networks, as these addresses are not routable on the public internet. Using private IP addresses allows multiple devices in a home or office to share a single public IP address when connecting to the internet. This separation ensures that internal communication remains internal while facilitating external communication through a router, which manages the traffic between the private network and the internet. This understanding clarifies why the other choices do not apply. Identifying devices on an external network or accessing public servers over the internet would typically involve public IP addresses. Similarly, directly accessing the internet without a router contradicts the fundamental networking principles that define how private and public IP addresses function.