What protocol defines a method for assigning IP addresses dynamically?

• A. IPSec
• B. DHCP
• C. ICMP
• D. FTP

Answer: (B)

The correct answer is DHCP, which stands for Dynamic Host Configuration Protocol. DHCP is a network management protocol used on IP networks that allows a server to automatically assign IP addresses and other network configuration parameters to devices (clients) on a network. This mechanism eliminates the need for manual configuration of each device's IP settings, which can be time-consuming and prone to errors, especially in large networks.

When a device connects to a network, it sends a request for an IP address to the DHCP server. The server then offers an available IP address along with other relevant network information like the subnet mask, default gateway, and DNS server addresses. This process ensures that each device on the network has a unique IP address, which is essential for communication within the network and on the internet.

In contrast, the other protocols mentioned serve very different purposes: IPSec is primarily used for securing IP communications by authenticating and encrypting each IP packet, ICMP (Internet Control Message Protocol) is used for diagnostic and error-handling functions in networking, and FTP (File Transfer Protocol) is designed for transferring files between systems. None of these protocols are involved in the dynamic assignment of IP addresses.