What service allows phones to download firmware and configuration files?

• A. FTP
• B. TFTP
• C. HTTP
• D. SSH

Answer: (B)

Phones use a lightweight file-transfer service to fetch their firmware and configuration during provisioning. This is TFTP, the Trivial File Transfer Protocol. It’s designed for simple, no-frills transfer over UDP, which makes it ideal for devices on a local network that need to boot up and load a firmware image or a configuration file with minimal setup. The phone points to a TFTP server to retrieve the necessary files when it boots or when provisioning is performed.

Other options are less suitable for this role. FTP is more feature-rich, uses TCP, and requires authentication, which adds complexity and firewall considerations. HTTP would require a web server and web-based requests, which isn’t as streamlined for device boot provisioning. SSH is for secure remote command access, not for distributing firmware or configurations. So the service that fits this use case best is TFTP.