NAME
tftp
—
trivial file transfer
program
SYNOPSIS
tftp |
[-e ] [host]
[port] |
DESCRIPTION
The tftp
utility 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.
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
orput
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 theconnect
command; the remote host can be specified as part of theget
orput
commands. get
filenameget
remotename localnameget
file1 file2 ... fileN- Get one or more files from the remote host. When using the
host argument, the host will
be used as default host for future transfers. If
localname is specified, the file is stored locally
as localname, otherwise the original filename is
used. Note that it is not possible to download two files at a time, only
one, three, or more than three files, at a time.
To specify an IPv6 numeric address for a host, wrap it using square brackets like “
[3ffe:2900:e00c:ffee::1234]
:file” to disambiguate the colons used in the IPv6 address from the colon separating the host and the filename. mode
transfer-mode- Set the mode for transfers; transfer-mode may be one
of
ascii
orbinary
. The default isascii
. put
fileput
localfile remotefileput
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. When
remotename is specified, the file is stored remotely
as remotename, otherwise the original filename is
used. If the remote-directory argument is used, the
remote host is assumed to be a UNIX machine. To
specify an IPv6 numeric address for a host, see the
example under the
get
command. 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.
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.
Files larger than 33488896 octets (65535 blocks) cannot be transferred without client and server supporting blocksize negotiation (RFC1783).