NAME

tftp — trivial file transfer program

SYNOPSIS

tftp	[-e] [host] [port]

DESCRIPTION

tftp is the user interface to the Internet TFTP (Trivial File Transfer Protocol), which allows users to transfer files to and from a remote machine. The remote host (and optional port) may be specified on the command line, in which case tftp uses host (and port) as the default for future transfers (see the connect command below).

The optional -e argument sets a binary transfer mode as well as setting the extended options as if tout, tsize, and blksize 65464, had been given.

The Multicast TFTP option is supported in open-loop (i.e., "slave-only") mode based on IETF draft-dion-tftp-multicast-option-01.txt (May 2002), which in turn was based on RFC2026.

COMMANDS

Once tftp is running, it issues the prompt ‘tftp>’ and recognizes the following commands:

? command-name ...

Print help information.

ascii

Shorthand for "mode ascii"

binary

Shorthand for "mode binary"

blksize blk-size

Set the tftp blksize option to blk-size octets (8-bit bytes). Since the number of blocks in a tftp get or put is 65535, the default block size of 512 bytes only allows a maximum of just under 32 megabytes to be transferred. The value given for blk-size must be between 8 and 65464, inclusive. Note that many servers will not respect this option.

connect host-name [port]

Set the host (and optionally port) for transfers. Note that the TFTP protocol, unlike the FTP protocol, does not maintain connections between transfers; thus, the connect command does not actually create a connection, but merely remembers what host is to be used for transfers. You do not have to use the connect command; the remote host can be specified as part of the get or put commands.

get filename

get remotename localname

get file1 file2 ... fileN

Get a file or set of files from the specified sources. Source can be in one of two forms: a filename on the remote host, if the host has already been specified, or a string of the form hosts:filename to specify both a host and filename at the same time. If the latter form is used, the last hostname specified becomes the default for future transfers.

mode transfer-mode

Set the mode for transfers; transfer-mode may be one of ascii or binary. The default is ascii.

put file

put localfile remotefile

put file1 file2 ... fileN remote-directory

Put a file or set of files to the specified remote file or directory. The destination can be in one of two forms: a filename on the remote host, if the host has already been specified, or a string of the form hosts:filename to specify both a host and filename at the same time. If the latter form is used, the hostname specified becomes the default for future transfers. If the remote-directory form is used, the remote host is assumed to be a UNIX machine. If you need to specify IPv6 numeric address to hosts, wrap them using square bracket like [hosts]:filename to disambiguate the colon.

quit

Exit tftp. An end of file also exits.

rexmt retransmission-timeout

Set the per-packet retransmission timeout, in seconds.

status

Show current status.

timeout total-transmission-timeout

Set the total transmission timeout, in seconds.

tout

Toggle the tftp "timeout" option. If enabled, the client will pass its retransmission-timeout to the server. Note that many servers will not respect this option.

trace

Toggle packet tracing.

tsize

Toggle the tftp "tsize" option. If enabled, the client will pass and request the filesize of a file at the beginning of a file transfer. Note that many servers will not respect this option.

verbose

Toggle verbose mode.

HISTORY

The tftp command appeared in 4.3BSD. IPv6 support was implemented by WIDE/KAME project in 1999. TFTP options were implemented by Wasabi Systems, Inc., in 2003, and first appeared in NetBSD 2.0. Multicast TFTP was implemented by Jared D. McNeill in 2006, and first appeared in NetBSD 4.0.

SECURITY CONSIDERATIONS

Because there is no user-login or validation within the TFTP protocol, the remote site will probably have some sort of file-access restrictions in place. The exact methods are specific to each site and therefore difficult to document here.