Trivial File Transfer Protocol
Trivial File Transfer Protocol (TFTP) uses UDP port 69 to transfer files between devices. Data transfer occurs between two UDP ports, where one is the source and the other the destination. TFTP is considered to possess weak security because the TFTP packet has no fields to authenticate with a username and password. Therefore, security is enabled by predefinition of the directories and filenames of files to be transferred to the TFTP server. This enables the remote hosts to TFTP the file from the remote TFTP client or server. Security relies on the application, not the operating system. TFTP is commonly used for upgrading Cisco IOS images on Cisco routers, Cisco switches, and Cisco security devices.