The transfer ends when a block arrives that is smaller than the standard 512 bytes.
A is a device or software application that uses the Trivial File Transfer Protocol (defined in RFC 1350) to send and receive files. Unlike FTP, which uses the robust TCP protocol, TFTP operates over UDP (User Datagram Protocol) , specifically on port 69.
The original 512-byte block size can make transferring large files (like 1GB OS images) very slow, though modern extensions (RFC 2348) allow for larger blocks. Best Practices for Running a TFTP Server If you are setting one up, keep these three rules in mind:
There is zero encryption . Anyone on the network can see the data being transferred. There is also no authentication—if you know the filename, you can usually grab it.
You might wonder why anyone would use a protocol without passwords or encryption. The answer lies in 1. Booting Diskless Workstations (PXE)
For every block sent, the receiver must send back an "Acknowledgment" (ACK) packet.