CompTIA Network+ Practice Test

What function does Automatic Private IP Addressing (APIPA) serve?

1. To connect multiple networks together without routers

2. To assign an IP address when a DHCP server is unavailable

3. To communicate across the internet without NAT

4. To provide static IPs for all local devices

The correct answer is: To assign an IP address when a DHCP server is unavailable

Automatic Private IP Addressing (APIPA) serves the specific function of assigning an IP address to a device on a local network when a Dynamic Host Configuration Protocol (DHCP) server is unavailable. This self-assigned address allows devices to communicate with each other within the same network segment without requiring manual configuration or a functioning DHCP server. When a device configured to use DHCP does not receive a valid IP address from the DHCP server, it will automatically assign itself an IP address from the APIPA range, which spans from 169.254.0.1 to 169.254.255.254. This feature ensures that local networking can still occur even when external configurations are compromised, allowing for limited connectivity in small networks or during troubleshooting situations. The other options do not accurately describe APIPA's function. For instance, APIPA does not facilitate the communication of multiple networks together or support internet communication without NAT. It also does not provide static IP addresses for devices, as the addresses assigned via APIPA are dynamic and specific to situations where no DHCP is available.