tftp.1   [plain text]


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.\"     @(#)tftp.1	8.2 (Berkeley) 4/18/94
.\" $FreeBSD: src/usr.bin/tftp/tftp.1,v 1.20 2007/11/07 07:56:57 ru Exp $
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.Dd June 11, 2003
.Dt TFTP 1
.Os
.Sh NAME
.Nm tftp
.Nd "trivial file transfer program"
.Sh SYNOPSIS
.Nm
.Op Fl e
.Op Ar host
.Op Ar port
.Sh DESCRIPTION
The
.Nm
utility is the user interface to the Internet
.Tn TFTP
(Trivial File Transfer Protocol),
which allows users to transfer files to and from a remote machine.
The remote
.Ar host
(and optional
.Ar port )
may be specified on the command line, in which case
.Nm
uses
.Ar host
(and
.Ar port )
as the default for future transfers (see the
.Cm connect
command below).
.Pp
The optional
.Fl e
argument sets a binary transfer mode as well as setting the extended options
as if
.Cm tout ,
.Cm tsize ,
and
.Cm blksize 65464 ,
had been given.
.Sh COMMANDS
Once
.Nm
is running, it issues the prompt
.Ql tftp\*[Gt]
and recognizes the following commands:
.Pp
.Bl -tag -width verbose -compact
.It Cm \&? Ar command-name ...
Print help information.
.Pp
.It Cm ascii
Shorthand for
.Ic mode Cm ascii .
.Pp
.It Cm binary
Shorthand for
.Ic mode Cm binary .
.Pp
.It Cm blksize Ar blk-size
Set the tftp blksize option to
.Ar blk-size
octets (8-bit bytes).  Since the number of blocks in a tftp
.Cm get
or
.Cm 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
.Ar blk-size
must be between 8 and 65464, inclusive.
Note that many servers will not respect this option.
.Pp
.It Cm connect Ar host-name Op Ar port
Set the
.Ar host
(and optionally
.Ar port )
for transfers.
Note that the
.Tn TFTP
protocol, unlike the
.Tn FTP
protocol,
does not maintain connections between transfers; thus, the
.Cm 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
.Cm connect
command; the remote host can be specified as part of the
.Cm get
or
.Cm put
commands.
.Pp
.It Cm get Ar filename
.It Cm get Ar remotename localname
.It Cm get Ar file1 file2 ...  fileN
Get one or more files from the remote host.
When using the
.Ar host
argument, the
.Ar host
will be used as default host for future transfers.
If
.Ar localname
is specified, the file is stored locally as
.Ar 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.
.Pp
To specify an IPv6 numeric address for a host, wrap it using square
brackets like
.Dq Li [3ffe:2900:e00c:ffee::1234] : Ns Ar file
to disambiguate the
colons used in the IPv6 address from the colon separating the host and
the filename.
.Pp
.It Cm mode Ar transfer-mode
Set the mode for transfers;
.Ar transfer-mode
may be one of
.Cm ascii
or
.Cm binary .
The default is
.Cm ascii .
.Pp
.It Cm put Ar file
.It Cm put Ar localfile remotefile
.It Cm put Ar 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
.Ar 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
.Ar remotename
is specified, the file is stored remotely as
.Ar remotename ,
otherwise the original filename is used.
If the
.Ar remote-directory
argument is used, the remote host is assumed to be a
.Ux
machine.
To specify an IPv6 numeric address for a
.Ar host ,
see the example under the
.Cm get
command.
.Pp
.It Cm quit
Exit
.Nm .
An end of file also exits.
.Pp
.It Cm rexmt Ar retransmission-timeout
Set the per-packet retransmission timeout, in seconds.
.Pp
.It Cm status
Show current status.
.Pp
.It Cm timeout Ar total-transmission-timeout
Set the total transmission timeout, in seconds.
.Pp
.It Cm tout
Toggle the tftp "timeout" option.  If enabled, the client will pass its
.Ar retransmission-timeout
to the server.
Note that many servers will not respect this option.
.Pp
.It Cm trace
Toggle packet tracing.
.Pp
.It Cm 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.
.Pp
.It Cm verbose
Toggle verbose mode.
.El
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.3 .
IPv6 support was implemented by WIDE/KAME project in 1999.
TFTP options were implemented by Wasabi Systems, Inc., in 2003,
and first appeared in
.Nx 2.0 .
.Sh SECURITY CONSIDERATIONS
Because there is no user-login or validation within
the
.Tn 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.
.Pp
Files larger than 33488896 octets (65535 blocks) cannot be transferred
without client and server supporting blocksize negotiation (RFC1783).