Trivial File Transfer Protocol

Trivial File Transfer Protocol (TFTP) is a UDP protocol used to transfer files. TFTP can read or write files from or to a remote server. On the z/OS® system, TFTP is a server you can configure with the command line option during TFTP invocation. TFTP can also be started as a procedure.

TFTP is installed in the /usr/lpp/tcpip/sbin/ directory.

Guideline: The TFTP server uses well-known port 69. The TFTP server has no user authentication. Any client that can connect to port 69 on the server has access to TFTP. If the TFTP server is started without a directory, it allows access to the entire file system. To restrict access to the file system, start the TFTP server with a list of directories.

The TFTP server preforks a child process to handle incoming requests when the concurrency limit is exceeded. Consequently, immediately after starting the TFTP server, two TFTP processes exist.

In case of a flood of concurrent TFTP commands, the TFTP server may fork additional processes. When the number of concurrent requests being processed drops below the concurrency limit, the number of TFTP processes is decreased back to two.