| Metric | Value | | :--- | :--- | | Default throughput (512B blocks) | Very low (≈1.2 MB/s on LAN due to ACK delay). | | Optimized (blksize 1456 bytes) | Up to ~10 MB/s on gigabit LAN. | | Windowed mode | Not in standard TFTP; requires proprietary extensions (e.g., tftp-multicast). | | Latency dependence | Highly sensitive to RTT; unusable over high-latency satellite links without blksize tuning. |
The TFTP server remains an essential but antiquated protocol for network bootstrap and device recovery. Its extreme simplicity is both its greatest strength (small code, low RAM) and its fatal weakness (no security, poor performance over high-latency links). System administrators must treat any TFTP server as a high-risk component and isolate it accordingly. Where possible, replacement with HTTPS-based booting or authenticated file transfer protocols offers a far superior security posture.
Appendix A: Related RFCs
Appendix B: Packet Capture Filter (tcpdump)
tcpdump -i eth0 -n 'udp port 69'
End of Report
Trivial File Transfer Protocol (TFTP) is the lightweight alternative to FTP, designed for simplicity and speed in local networks. Because it lacks authentication and encryption, it is primarily used for booting diskless workstations and updating firmware on network devices like routers and switches. Core Features of TFTP
Minimalist Protocol: No directory listing, user login, or file management. TFTP Server
UDP Driven: Operates on UDP Port 69 for fast, low-overhead transfers.
Small Footprint: Ideal for embedded systems and bootloaders with limited memory. | Metric | Value | | :--- |
Lockstep Transmission: Sends data in 512-byte blocks, requiring an acknowledgment (ACK) for each before the next is sent. Common Use Cases How to Configure TFTP Server for Network Boot on Ubuntu
Preboot Execution Environment (PXE) uses TFTP to download a bootloader, kernel, or installer image. When you install an OS over the network (e.g., with FOG or WDS), the client gets a tiny DHCP-assigned IP, then TFTP pulls the first-stage boot file. Appendix A: Related RFCs