What protocol is used to assign IP addresses dynamically to devices on a network?

Dynamic Host Configuration Protocol, commonly known as DHCP, is specifically designed to automate the process of assigning IP addresses to devices within a network. When a device connects to a network, it sends a request to a DHCP server, which then selects an available IP address from a predefined range and assigns it to the device along with other necessary network configuration details, such as the subnet mask, default gateway, and DNS server addresses. This dynamic assignment eliminates the need for manual IP address configuration, reducing the chances of errors and conflicts, particularly in larger networks.

The other protocols listed serve different purposes: FTP is used for transferring files, HTTP is for serving web pages, and SMTP is employed for sending emails. None of these protocols deal with the allocation of IP addresses, making DHCP the correct answer in the context of dynamic IP assignment.