tftp(1)tftp(1)NAMEtftp - Provides the Trivial File Transfer Protocol (TFTP)
SYNOPSIS
Interactive form: tftp [remote_host] [port]
Command-line form: tftp remote_host [port] -subcommand [args]
DESCRIPTION
The tftp command transfers files between hosts using TFTP. Because TFTP
is a minimal file transfer protocol, the tftp command does not provide
all of the features described under the ftp command. For example, tftp
does not provide subcommands to list remote files or change directories
at the remote host, and limited file access privileges are given to the
remote TFTP server. Note that the tftp command is not available when
your host is operating in controlled access (secure) mode.
The remote host must have a tftpd server started by its inetd server
and have an account defined that limits the access of tftpd. Use the
tftpd command to set up the TFTP environment and the nobody account.
The tftp command has two forms: interactive form and command line form.
In the interactive form, tftp is issued alone or with a host argument
that specifies the default host to use for file transfers during this
session. You can also specify a port for the tftp connection to use.
When you enter the interactive form, the tftp> prompt appears. In the
command line form, you specify command arguments on the command line,
and no prompt appears. The tftp command can overwrite a file, but
prompts you before doing so.
When transferring data to a remote host, the transferred data is placed
in the directory specified by the remote_file argument. remote_file
must be a fully specified filename, and the remote file must both exist
and have write permission set for others. The tftp command attempts to
write the data to the specified file. However, if the remote TFTP
server does not have the appropriate privileges to write the remote
file or if the file does not already exist, the transfer fails.
SUBCOMMANDS
The tftp subcommands can be entered in either their interactive form or
in their command line form. Displays help information. If a subcom‐
mand is specified, only information about that subcommand is displayed.
Synonym for the mode ascii subcommand. Synonym for the mode binary
subcommand. This subcommand is used in the interactive mode. The image
mode is the same as mode binary, but is used on the command line. Sets
the data block size in bytes. Specify a value in the range 8 to 65464.
The default block size is 512 bytes. Packet size is equivalent to the
blocksize +4 bytes (516 bytes by default).
The value of blocksize is constrained by the size of the UDP
socket send buffer. Before setting the block size to a large
value, you should verify the size of the UDP socket send buffer.
This buffer has a default size of 9216 bytes. You can increase
the buffer size by modifying the value of the udp_sendspace sys‐
tem configuration parameter. Refer to the sys_attrs(5) and
sys_attrs_inet(5) reference pages for more information on check‐
ing and setting the udp_sendspace parameter. Sets the remote
host, and optionally the port, for file transfers. Because the
TFTP protocol does not maintain connections between transfers,
the connect subcommand does not create a connection to host, but
stores the settings for transfer operations. Because the remote
host can be specified as part of the get or put subcommands,
which overrides any host previously specified, the connect sub‐
command is not required. Transfers a file or set of files from
the remote host to the local host. Each of the remote_file
arguments can be specified in one of the following two ways: As
a file that exists on the remote host, if a default host was
already specified. As host:file, where host is the remote host
and file is the name of the file to copy to the local system.
If this form of the argument is used, the host specified for the
last transfer becomes the default host for subsequent transfers
in this tftp session.
In either case, remote_file must be a fully-specified filename.
Toggles hash marks. Sets the transfer mode to ascii or binary.
A transfer mode of ascii is the default. Sets mode to octet.
Transfers a file or set of files from the local host onto the
remote host. The remote_directory and remote_file arguments can
be specified in one of the following two ways: As a file or
directory that exists on the remote host, if a default host was
already specified. As host:remote_file, where host is the
remote host and remote_file is the name of the file or directory
on the remote system. If this form of the argument is used, the
host specified for the last transfer becomes the default host
for subsequent transfers in this tftp session.
In either of these cases, the remote filename or directory name
must be a full pathname, even if the local and remote directo‐
ries have the same name. If a remote directory is specified, the
remote host is assumed to use UNIX pathname syntax. Exits tftp.
An End-of-File also exits the program. Displays transfer rate
information. Defines the retransmission time-out for each
packet, in seconds. Shows the current status of tftp, including
the current transfer mode (ascii or binary), connection status,
time-out value, and so on. Sets the total transmission time-out
to the number of seconds specified by value. Turns packet trac‐
ing on or off. Turns verbose mode, which displays additional
information during file transfer, on or off.
EXAMPLES
To enter tftp, check the current status, connect to host1, and transfer
the file update from host1 to the local host, enter: $ tftp tftp> sta‐
tus
Not connected. Mode: netascii Verbose: off Tracing: off Rexmt_inter‐
val: 5 seconds, Max-timeout: 25 seconds
tftp> connect host1 tftp> get /u/alice/update update tftp> quit $
The get subcommand transfers the file update from the remote
host to your local host. Note that the directory /u/alice on the
remote host must have read permission set for others.
To perform the same operation in command-line mode, enter: $
tftp host1 -status-get /u/alice/update update Connected to
host1. Mode: netascii Verbose: off Tracing: off Rexmt_inter‐
val: 5 seconds, Max-timeout: 25 seconds
To open a tftp connection to host1, set binary mode, transfer
the file game.exe from the local host to host1, and rename the
file in the process, enter: $ tftp host1 tftp> binary tftp> put
game.exe /u/alice/tictactoe.exe
The put subcommand transfers the file game.exe from your local
host to the remote host as tictactoe.exe. Note that the direc‐
tory /u/alice on the remote host must have write permission set
for others. Also, the file tictactoe.exe must already exist on
the server and have write permission set for others.
To perform the same operation in command-line mode, enter: $
tftp host1 -binary -put game.exe /u/alice/tictactoe.exe
To transfer two files from the local host to two remote hosts,
enter: $ tftp tftp> put product.html pricelist.html
host1:/u/alice/public_html tftp> put product.html pricelist.html
host2:/public/documents
The put subcommand transfers the files from your local host to
the specified directory on each remote host. Again, the files
and directories must already exist on the remote hosts and have
write permissions set for others. When the file transfer is com‐
plete, the last host, host2, becomes the default host for subse‐
quent transfers in this tftp session.
To perform the same operation in command-line mode, enter: $
tftp host1 -put product.html pricelist.html /u/alice/public_html
$ tftp host2 -put product.html pricelist.html /public/documents
FILES
Defines the address of the local host, and specifies the names and
addresses of remote hosts. Defines the sockets and protocols used for
Internet services.
SEE ALSO
Commands: ftp(1), ftpd(8), inetd(8), rcp(1), syslogd(8), tftpd(8)tftp(1)
