This is inetutils.info, produced by makeinfo version 4.3 from
../../inetutils/doc/inetutils.texi.
START-INFO-DIR-ENTRY
* networking(inet) utilities: (inetutils). GNU networking utilities.
* ftp: (inetutils)ftp invocation. File Transfer Protocol.
* ftpd: (inetutils)ftpd invocation. FTP Daemon.
* inetd: (inetutils)inetd invocation. Interner super-server.
* ping: (inetutils)ping invocation. Packets to network hosts.
* rcp: (inetutils)rcp invocation. Strip non-directory suffix.
* rexecd: (inetutils)rexecd invocation. Remote execution server.
* rlogin: (inetutils)rlogin invocation. Remote login.
* rlogind: (inetutils)rlogind invocation. Remote login server.
* rsh: (inetutils)rsh invocation. Remote shell.
* rshd: (inetutils)rshd invocation. Remote shell server.
* logger: (inetutils)logger invocation. Logger.
* syslogd: (inetutils)syslogd invocation. Syslog server.
* talk: (inetutils)talk invocation. Talk client.
* talkd: (inetutils)talkd invocation. Talk server.
* tftp: (inetutils)tftp invocation. Trivial FTP.
END-INFO-DIR-ENTRY
This file documents the GNU networking utilities.
Copyright (C) 1994, 95, 96, 2000, 2001 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.
File: inetutils.info, Node: Top, Next: Introduction, Up: (dir)
GNU networking utilities
************************
This manual documents version 1.4.2 of the GNU network utilities.
* Menu:
* Introduction:: Caveats, overview, and authors.
* ftp:: File Transfer Protocol.
* ftpd:: FTP Daemon.
* inetd:: Interner super-server.
* ping:: Packets to network hosts.
* rcp:: Strip non-directory suffix.
* rexecd:: Remote execution server.
* rlogin:: Remote login.
* rlogind:: Remote login server.
* rsh:: Remote shell.
* rshd:: Remote shell server.
* logger:: Logger.
* syslogd:: Syslog server.
* talk:: Talk client.
* talkd:: Talk server.
* tftp:: Trivial FTP.
* Reporting Bugs:: How to report bugs.
* Concept Index:: Index of concepts.
* Index:: Index of commands, options and variables.
File: inetutils.info, Node: Introduction, Next: ftp, Prev: Top, Up: Top
Introduction
************
The individual utilities was originally derived from the 4.4BSDLite2
distribution. Many features were integrated from NetBSD, OpenBSD,
FreeBSD and GNU/Linux, the merges were done by a group of dedicated
hackers (in no particular order): Jeff Bailey, Marcus Brinkmann,
Michael Vogt, Bernhard Rosenkraenzer, Kaveh R. Ghazi, NIIBE Yutaka,
Nathan Neulinger, Jeff Smith, Dan Stromberg, David O'Shea, Frederic
Goudal, Gerald Combs, Joachim Gabler, Marco D'Itri.
Certain options are available in all these programs. Rather than
writing identical descriptions for each of the programs, they are
described here. (In fact, every GNU program accepts (or should accept)
these options.)
Many of these programs take arbitrary strings as arguments. In those
cases, `--help' and `--version' are taken as these options only if
there is one and exactly one command line argument.
`--help'
Print a usage message listing all available options, then exit
successfully.
`-V'
`--version'
Print the version number, then exit successfully.
File: inetutils.info, Node: ftp, Next: ftpd, Prev: Introduction, Up: Top
ftp
***
`Ftp' is the user interface to the ARPANET standard File Transfer
Protocol. The program allows a user to transfer files to and from a
remote network site.
Invoking
========
The options are as follows:
`-d'
`--debug'
Enables debugging.
`-g'
`--no-glob'
Disables file name globbing.
`-i'
`--no-prompt'
Turns off interactive prompting during multiple file transfers.
`-n'
`--no-login'
Restrains ftp from attempting "auto-login" upon initial connection.
If auto-login is enabled, ftp will check the .netrc (see below)
file in the user's home directory for an entry describing an
account on the remote machine. If no entry exists, ftp will
prompt for the remote machine login name (default is the user
identity on the local machine), and, if necessary, prompt for a
password and an account with which to login.
`-t'
`--trace'
Enable packet tracing.
`-p PROMPT'
`--prompt=PROMPT'
Print a command-line prompt (optionally PROMPT), even if not on a
tty.
`-v'
`--verbose'
Be verbose.
Commands
========
The client host with which ftp is to communicate may be specified on
the command line. If this is done, ftp will immediately attempt to
establish a connection to an FTP server on that host; otherwise, ftp
will enter its command interpreter and await instructions from the
user. When ftp is awaiting commands from the user the prompt `ftp>' is
provided to the user. The following commands are recognized by ftp:
`! [command [args]]'
Invoke an interactive shell on the local machine. If there are
arguments, the first is taken to be a command to execute directly,
with the rest of the arguments as its arguments.
`$ macro-name [args]'
Execute the macro macro-name that was defined with the macdef
command. Arguments are passed to the macro unglobbed.
`account [passwd]'
Supply a supplemental password required by a remote system for
access to resources once a login has been successfully completed.
If no argument is included, the user will be prompted for an
account password in a non-echoing input mode.
`append local-file [remote-file]'
Append a local file to a file on the remote machine. If
remote-file is left unspecified, the local file name is used in
naming the remote file after being altered by any ntrans or nmap
setting. File transfer uses the current settings for type,
format, mode, and structure.
`ascii'
Set the file transfer type to network ASCII. This is the default
type.
`bell'
Arrange that a bell be sounded after each file transfer command is
completed.
`binary'
Set the file transfer type to support binary image transfer.
`bye'
Terminate the FTP session with the remote server and exit ftp. An
end of file will also terminate the session and exit.
`case'
Toggle remote computer file name case mapping during mget
commands. When case is on (default is off), remote computer file
names with all letters in upper case are written in the local
directory with the letters mapped to lower case.
`cd remote-directory'
Change the working directory on the remote machine to
remote-directory.
`cdup'
Change the remote machine working directory to the parent of the
current remote machine working directory.
`chmod mode file-name'
Change the permission modes of the file file-name on the re- mote
sytem to mode.
`close'
Terminate the FTP session with the remote server, and return to
the command interpreter. Any defined macros are erased.
`cr'
Toggle carriage return stripping during ascii type file retrieval.
Records are denoted by a carriage return/linefeed sequence during
ascii type file transfer. When cr is on (the default), carriage
returns are stripped from this sequence to conform with the UNIX
single linefeed record delimiter. Records on non-UNIX remote
systems may contain single linefeeds; when an ascii type transfer
is made, these linefeeds may be distinguished from a record
delimiter only when cr is off.
`delete remote-file'
Delete the file remote-file on the remote machine.
`debug [debug-value]'
Toggle debugging mode. If an optional debug-value is specified it
is used to set the debugging level. When debugging is on, ftp
prints each command sent to the remote machine, preceded by the
string `->'
`dir [remote-directory] [local-file]'
Print a listing of the directory contents in the directory,
remote-directory, and, optionally, placing the output in
local-file. If interactive prompting is on, ftp will prompt the
user to verify that the last argument is indeed the tar- get local
file for receiving dir output. If no directory is specified, the
current working directory on the remote ma- chine is used. If no
local file is specified, or local-file is -, output comes to the
terminal.
`disconnect'
A synonym for close.
`form format'
Set the file transfer form to format. The default format is "file".
`get remote-file [local-file]'
Retrieve the remote-file and store it on the local machine. If
the local file name is not specified, it is given the same name it
has on the remote machine, subject to alteration by the current
case, ntrans, and nmap settings. The current settings for type,
form, mode, and structure are used while transferring the file.
`glob'
Toggle filename expansion for mdelete, mget and mput. If globbing
is turned off with glob, the file name arguments are taken
literally and not expanded. Globbing for mput is done as in
csh(1). For mdelete and mget, each remote file name is expanded
separately on the remote machine and the lists are not merged.
Expansion of a directory name is likely to be different from
expansion of the name of an ordinary file: the exact result
depends on the foreign operating system and ftp server, and can be
previewed by doing `mls remote-files -' Note: mget and mput are
not meant to transfer entire directo- ry subtrees of files. That
can be done by transferring a tar(1) archive of the subtree (in
binary mode).
`hash [size]'
Toggle hash-sign ("#") printing for each data block transferred.
The size of a data block can optionally be specified. If not
given, it defaults to 1024 bytes.
`help [command]'
Print an informative message about the meaning of command. If no
argument is given, ftp prints a list of the known commands.
`idle [seconds]'
Set the inactivity timer on the remote server to seconds seconds.
If seconds is omitted, the current inactivity timer is printed.
`lcd [directory]'
Change the working directory on the local machine. If no
directory is specified, the user's home directory is used.
`ls [remote-directory] [local-file]'
Print a listing of the contents of a directory on the remote
machine. The listing includes any system-dependent information
that the server chooses to include; for example, most UNIX systems
will produce output from the command `ls -l'. (See also nlist.)
If remote-directory is left unspecified, the current working
directory is used. If interactive prompting is on, ftp will
prompt the user to verify that the last argument is indeed the
target local file for receiving ls output. If no local file is
specified, or if local-file is `-', the output is sent to the
terminal.
`macdef macro-name'
Define a macro. Subsequent lines are stored as the macro
macro-name; a null line (consecutive newline characters in a file
or carriage returns from the terminal) terminates macro input
mode. There is a limit of 16 macros and 4096 total characters in
all defined macros. Macros remain defined until a close command
is executed. The macro processor interprets `$' and `\' as
special characters. A `$' followed by a number (or numbers) is
replaced by the corresponding argument on the macro invocation
command line. A `$' followed by an `i' signals that macro
processor that the executing macro is to be looped. On the first
pass `$i' is replaced by the first argument on the macro
invocation command line, on the second pass it is replaced by the
second argument, and so on. A `\' followed by any character is
replaced by that character. Use the `\' to prevent special
treatment of the `$'.
`mdelete [remote-files]'
Delete the remote-files on the remote machine.
`mdir remote-files local-file'
Like dir, except multiple remote files may be specified. If
interactive prompting is on, ftp will prompt the user to verify
that the last argument is indeed the target local file for
receiving mdir output.
`mget remote-files'
Expand the remote-files on the remote machine and do a get for
each file name thus produced. See glob for details on the
filename expansion. Resulting file names will then be processed
according to case, ntrans, and nmap settings. Files are
transferred into the local working directory, which can be changed
with `lcd directory'; new local directories can be created with `!
mkdir directory'.
`mkdir directory-name'
Make a directory on the remote machine.
`mls remote-files local-file'
Like nlist, except multiple remote files may be specified, and the
local-file must be specified. If interactive prompting is on, ftp
will prompt the user to verify that the last argument is indeed
the target local file for receiving mls output.
`mode [mode-name]'
Set the file transfer mode to mode-name. The default mode is
"stream" mode.
`modtime file-name'
Show the last modification time of the file on the remote machine.
`mput local-files'
Expand wild cards in the list of local files given as arguments
and do a put for each file in the resulting list. See glob for
details of filename expansion. Resulting file names will then be
processed according to ntrans and nmap settings.
`newer file-name'
Get the file only if the modification time of the remote file is
more recent that the file on the current system. If the file does
not exist on the current system, the remote file is considered
newer. Otherwise, this command is identical to get.
`nlist [remote-directory] [local-file]'
Print a list of the files in a directory on the remote machine.
If remote-directory is left unspecified, the current working
directory is used. If interactive prompting is on, ftp will
prompt the user to verify that the last argument is indeed the
target local file for receiving nlist output. If no local file is
specified, or if local-file is -, the output is sent to the
terminal.
`nmap [inpattern outpattern]'
Set or unset the filename mapping mechanism. If no arguments are
specified, the filename mapping mechanism is unset. If arguments
are specified, remote filenames are mapped during mput commands
and put commands issued without a specified remote target
filename. If arguments are specified, local filenames are mapped
during mget commands and get commands issued without a specified
local target filename. This command is useful when connecting to
a non-UNIX remote computer with different file naming conventions
or practices. The mapping follows the pattern set by inpattern
and outpattern. [Inpattern] is a template for incoming filenames
(which may have already been processed according to the ntrans and
case settings). Variable templating is accomplished by including
the sequences `$1', `$2', ..., `$9' in inpattern. Use `\' to
prevent this special treatment of the `$' character. All other
characters are treated literally, and are used to de- termine the
nmap [inpattern] variable values. For example, given inpattern
$1.$2 and the remote file name "mydata.data", $1 would have the
value "mydata", and $2 would have the value data". The outpattern
determines the resulting mapped filename. The sequences `$1',
`$2', ...., `$9' are replaced by any value resulting from the
inpattern template. The sequence `$0' is replace by the original
filename. Additionally, the sequence `[seq1, seq2]' is replaced
by [seq1] if seq1 is not a null string; otherwise it is replaced
by seq2. For example, the command
nmap $1.$2.$3 [$1,$2].[$2,file]
would yield the output filename "myfile.data" for input filenames
"myfile.data" and "myfile.data.old", "myfile.file" for the input
filename "myfile", and "myfile.myfile" for the in- put filename
".myfile". Spaces may be included in outpattern, as in the
example: `nmap $1 sed "s/ *$//" > $1'. Use the `\' character to
prevent special treatment of the `$','[','[', and `,' characters.
`ntrans [inchars [outchars]]'
Set or unset the filename character translation mechanism. If no
arguments are specified, the filename character translation
mechanism is unset. If arguments are specified, characters in
remote filenames are translated during mput commands and put
commands issued without a specified remote target filename. If
arguments are specified, characters in local filenames are
translated during mget commands and get commands issued without a
specified local target filename. This command is useful when
connecting to a non-UNIX remote computer with different file
naming conventions or practices. Characters in a filename
matching a character in inchars are replaced with the
corresponding character in outchars. If the character's position
in inchars is longer than the length of outchars, the character is
deleted from the file name.
`open host [port]'
Establish a connection to the specified host FTP server. An
optional port number may be supplied, in which case, ftp will
attempt to contact an FTP server at that port. If the autologin
option is on (default), ftp will also attempt to automatically log
the user in to the FTP server (see below).
`passive'
Toggle passive mode. If passive mode is turned on (default is
off), the ftp client will send a PASV command for all data
connections instead of the usual PORT command. The PASV com- mand
requests that the remote server open a port for the data
connection and return the address of that port. The remote server
listens on that port and the client connects to it. When using
the more traditional PORT command, the client listens on a port
and sends that address to the remote server, who connects back to
it. Passive mode is useful when using ftp through a gateway
router or host that controls the directionality of traffic. (Note
that though ftp servers are required to support the PASV command
by RFC 1123, some do not.)
`prompt'
Toggle interactive prompting. Interactive prompting occurs during
multiple file transfers to allow the user to selectively retrieve
or store files. If prompting is turned off (default is on), any
mget or mput will transfer all files, and any mdelete will delete
all files.
`proxy ftp-command'
Execute an ftp command on a secondary control connection. This
command allows simultaneous connection to two remote ftp servers
for transferring files between the two servers. The first proxy
command should be an open, to establish the secondary control
connection. Enter the command "proxy ?" to see other ftp commands
executable on the secondary connection. The following commands
behave differently when prefaced by proxy: open will not define
new macros during the auto-login process, close will not erase
existing macro definitions, get and mget transfer files from the
host on the primary control connection to the host on the
secondary control connection, and put, mput, and append transfer
files from the host on the secondary control connection to the
host on the primary control connection. Third party file
transfers depend upon support of the ftp protocol PASV command by
the server on the secondary control connection.
`put local-file [remote-file]'
Store a local file on the remote machine. If remote-file is left
unspecified, the local file name is used after processing according
to any ntrans or nmap settings in naming the remote file. File
transfer uses the current settings for type, format, mode, and
structure.
`pwd'
Print the name of the current working directory on the remote
machine.
`quit'
A synonym for bye.
`quote arg1 arg2 ...'
The arguments specified are sent, verbatim, to the remote FTP
server.
`recv remote-file [local-file]'
A synonym for get.
`reget remote-file [local-file]'
Reget acts like get, except that if local-file exists and is
smaller than remote-file, local-file is presumed to be a partially
transferred copy of remote-file and the transfer is continued from
the apparent point of failure. This command is useful when
transferring very large files over networks that are prone to
dropping connections.
`remotehelp [command-name]'
Request help from the remote FTP server. If a command-name is
specified it is supplied to the server as well.
`remotestatus [file-name]'
With no arguments, show status of remote machine. If filename is
specified, show status of file-name on remote machine.
`rename [from] [to]'
Rename the file from on the remote machine, to the file to.
`reset'
Clear reply queue. This command re-synchronizes command/reply
sequencing with the remote ftp server. Resynchronization may be
necessary following a violation of the ftp protocol by the remote
server.
`restart marker'
Restart the immediately following get or put at the indicated
marker. On UNIX systems, marker is usually a byte offset into the
file.
`rmdir directory-name'
Delete a directory on the remote machine.
`runique'
Toggle storing of files on the local system with unique filenames.
If a file already exists with a name equal to the target local
filename for a get or mget command, a ".1" is appended to the
name. If the resulting name matches another existing file, a ".2"
is appended to the original name. If this process continues up to
".99", an error message is printed, and the transfer does not take
place. The generated unique filename will be reported. Note that
runique will not affect local files generated from a shell command
(see below). The default value is off.
`send local-file [remote-file]'
A synonym for put.
`sendport'
Toggle the use of PORT commands. By default, ftp will attempt to
use a PORT command when establishing a connection for each data
transfer. The use of PORT commands can prevent delays when
performing multiple file transfers. If the PORT command fails,
ftp will use the default data port. When the use of PORT commands
is disabled, no attempt will be made to use PORT commands for each
data transfer. This is useful for certain FTP implementations
which do ignore PORT commands but, incorrectly, indicate they've
been accepted.
`site arg1 arg2 ...'
The arguments specified are sent, verbatim, to the remote FTP
server as a SITE command.
`size file-name'
Return size of file-name on remote machine.
`status'
Show the current status of ftp.
`struct [struct-name]'
Set the file transfer structure to struct-name. By default
"stream" structure is used.
`sunique'
Toggle storing of files on remote machine under unique file names.
Remote ftp server must support ftp protocol STOU command for
successful completion. The remote server will report unique name.
Default value is off.
`system'
Show the type of operating system running on the remote machine.
`tenex'
Set the file transfer type to that needed to talk to TENEX
machines.
`trace'
Toggle packet tracing.
`type [type-name]'
Set the file transfer type to type-name. If no type is specified,
the current type is printed. The default type is net- work ASCII.
`umask [newmask]'
Set the default umask on the remote server to newmask. If newmask
is omitted, the current umask is printed.
`user user-name [password] [account]'
Identify yourself to the remote FTP server. If the password is
not specified and the server requires it, ftp will prompt the user
for it (after disabling local echo). If an account field is not
specified, and the FTP server requires it, the user will be
prompted for it. If an account field is specified, an account
command will be relayed to the remote server after the login
sequence is completed if the remote server did not require it for
logging in. Unless ftp is invoked with "auto-login" disabled,
this process is done automatically on initial connection to the
FTP server.
`verbose'
Toggle verbose mode. In verbose mode, all responses from the FTP
server are displayed to the user. In addition, if verbose is on,
when a file transfer completes, statistics regarding the
efficiency of the transfer are reported. By default, verbose is
on.
`? [command]'
A synonym for help.
Command arguments which have embedded spaces may be quoted with
quote `"' marks.
Aborting A File Transfer
========================
To abort a file transfer, use the terminal interrupt key (usually
Ctrl-C). Sending transfers will be immediately halted. Receiving
transfers will be halted by sending a ftp protocol ABOR command to the
remote server, and discarding any further data received. The speed at
which this is accomplished depends upon the remote server's support for
ABOR processing. If the remote server does not support the ABOR
command, an `ftp>' prompt will not appear until the remote server has
completed sending the requested file.
The terminal interrupt key sequence will be ignored when ftp has
completed any local processing and is awaiting a reply from the remote
server. A long delay in this mode may result from the ABOR processing
described above, or from unexpected behavior by the remote server,
including violations of the ftp protocol. If the delay results from
unexpected remote server behavior, the local ftp program must be killed
by hand.
File Naming Conventions
=======================
Files specified as arguments to ftp commands are processed according
to the following rules.
1. If the file name `-' is specified, the stdin (for reading) or
stdout (for writing) is used.
2. If the first character of the file name is `|', the remainder of
the argument is interpreted as a shell command. Ftp then forks a
shell, using popen(3) with the argument supplied, and reads
(writes) from the stdout (stdin). If the shell command includes
spaces, the argument must be quoted; e.g. "" ls -lt"". A
particularly useful example of this mechanism is: "dir more".
3. Failing the above checks, if "globbing" is enabled, local file
names are expanded according to the rules used in the csh(1); c.f.
the glob command. If the ftp command expects a single local file
(.e.g. put), only the first filename generated by the "globbing"
operation is used.
4. For mget commands and get commands with unspecified local file
names, the local filename is the remote filename, which may be
altered by a case, ntrans, or nmap setting. The resulting filename
may then be altered if runique is on.
5. For mput commands and put commands with unspecified remote file
names, the remote filename is the local filename, which may be
altered by a ntrans or nmap setting. The resulting filename may
then be altered by the remote server if sunique is on.
File Transfer Parameters
========================
The FTP specification specifies many parameters which may affect a
file transfer. The type may be one of "ascii", "image" (binary),
"ebcdic", and "local byte size" (for PDP-10's and PDP-20's mostly).
Ftp supports the ascii and image types of file transfer, plus local byte
size 8 for tenex mode transfers.
Ftp supports only the default values for the remaining file transfer
parameters: mode, form, and struct.
The `.netrc' File
=================
The .netrc file contains login and initialization information used
by the auto-login process. It resides in the user's home directory.
The following tokens are recognized; they may be separated by spaces,
tabs, or new-lines:
`machine name'
Identify a remote machine name. The auto-login process searches
the .netrc file for a machine token that matches the remote ma-
chine specified on the ftp command line or as an open command
argument. Once a match is made, the subsequent .netrc tokens are
processed, stopping when the end of file is reached or an- other
machine or a default token is encountered.
`default'
This is the same as machine name except that default matches any
name. There can be only one default token, and it must be after
all machine tokens. This is normally used as:
default login anonymous password user@site
thereby giving the user automatic anonymous ftp login to machines
not specified in .netrc. This can be overridden by using the -n
flag to disable auto-login.
`login name'
Identify a user on the remote machine. If this token is present,
the auto-login process will initiate a login using the specified
name.
`password string'
Supply a password. If this token is present, the auto-login
process will supply the specified string if the remote server
requires a password as part of the login process. Note that if
this token is present in the .netrc file for any user other than
anonymous, ftp will abort the auto-login process if the `.netrc'
is readable by anyone besides the user.
`account string'
Supply an additional account password. If this token is present,
the auto-login process will supply the specified string if the
remote server requires an additional account password, or the
auto-login process will initiate an ACCT command if it does not.
`macdef name'
Define a macro. This token functions like the ftp macdef command
functions. A macro is defined with the specified name; its
contents begin with the next .netrc line and continue until a null
line (consecutive new-line characters) is encountered. If a macro
named init is defined, it is automatically executed as the last
step in the auto-login process.
Ftp utilizes the following environment variables.
`HOME'
For default location of a .netrc file, if one exists.
`SHELL'
For default shell.
Correct execution of many commands depends upon proper behavior by
the remote server.
An error in the treatment of carriage returns in the 4.2BSD
ascii-mode transfer code has been corrected. This correction may
result in incorrect transfers of binary files to and from 4.2BSD
servers using the ascii type. Avoid this problem by using the binary
image type.
File: inetutils.info, Node: ftpd, Next: inetd, Prev: ftp, Up: Top
ftpd
****
`Ftpd' is the Internet File Transfer Protocol server process. The
server uses the TCP protocol and listens at the port specified in the
"ftp" service specification; see services(5).
Invoking
========
The options are as follows:
`-A'
`--anonymous-only'
Only anonymous login is allowed.
`-a AUTH'
`--auth=AUTH'
Give anonymous an other login-name (anonymous and ftpd will still
work).
`-D'
`--daemon'
`ftpd' enters daemon-mode. That allows ftpd to be run without
inetd.
`-d'
`--debug'
Debugging information is written to the syslog using LOG_FTP.
`-l'
`--logging'
Each successful and failed ftp(1) session is logged using syslog
with a facility of LOG_FTP. If this option is specified twice,
the retrieve (get), store (put), append, delete, make directory,
remove directory and rename operations and their filename
arguments are also logged.
`-p PIDFILE'
`--pidfile=PIDFILE'
Change default location of PIDFILE
`-q'
`--no-version'
Quiet mode. No information about the version of the ftpd is given
to the client.
`-T'
`--max-timeout'
A client may also request a different timeout period; the maximum
period allowed may be set to timeout seconds with the -T option.
The default limit is 2 hours.
`-t TIMEOUT'
`--timeout=TIMEOUT'
The inactivity timeout period is set to timeout seconds (the
default is 15 minutes).
`-u UMASK'
`--umask=UMASK'
Set default umask(base 8).
The file `/etc/nologin' can be used to disable ftp access. If the
file exists, ftpd displays it and exits. If the file `/etc/ftpwelcome'
exists, `ftpd' prints it before issuing the "ready" message. If the
file `/etc/motd' exists, ftpd prints it after a successful login.
The ftp server currently supports the following ftp requests. The
case of the requests is ignored.
Request Description
ABOR abort previous command
ACCT specify account (ignored)
ALLO allocate storage (vacuously)
APPE append to a file
CDUP change to parent of current working directory
CWD change working directory
DELE delete a file
HELP give help information
LIST give list files in a directory (``ls -lgA'')
MKD make a directory
MDTM show last modification time of file
MODE specify data transfer mode
NLST give name list of files in directory
NOOP do nothing
PASS specify password
PASV prepare for server-to-server transfer
PORT specify data connection port
PWD print the current working directory
QUIT terminate session
REST restart incomplete transfer
RETR retrieve a file
RMD remove a directory
RNFR specify rename-from file name
RNTO specify rename-to file name
SITE non-standard commands (see next section)
SIZE return size of file
STAT return status of server
STOR store a file
STOU store a file with a unique name
STRU specify data transfer structure
SYST show operating system type of server system
TYPE specify data transfer type
USER specify user name
XCUP change to parent of current working directory
(deprecated)
XCWD change working directory (deprecated)
XMKD make a directory (deprecated)
XPWD print the current working directory (deprecated)
XRMD remove a directory (deprecated)
The following non-standard or UNIX specific commands are supported by the
SITE request.
Request Description
UMASK change umask, e.g. ``SITE UMASK 002''
IDLE set idle-timer, e.g. ``SITE IDLE 60''
CHMOD change mode of a file, e.g. ``SITE CHMOD0 0CHMOD1
1CHMOD2
HELP give help information.
The remaining ftp requests specified in Internet RFC 959 are
recognized, but not implemented. MDTM and SIZE are not specified in
RFC 959, but will appear in the next updated FTP RFC.
The ftp server will abort an active file transfer only when the ABOR
com- mand is preceded by a Telnet "Interrupt Process" (IP) signal and a
Telnet Synch" signal in the command Telnet stream, as described in
Internet RFC 959. If a STAT command is received during a data
transfer, preceded by a Telnet IP and Synch, transfer status will be
returned.
Ftpd interprets file names according to the "globbing" conventions
used by csh(1). This allows users to utilize the metacharacters
"*?[]{}~".
Ftpd authenticates users according to three rules.
1. The login name must be in the password data base, `/etc/passwd',
and not have a null password. In this case a password must be
provided by the client before any file operations may be per-
formed.
2. The login name must not appear in the file `/etc/ftpusers'.
3. The user must have a standard shell returned by getusershell(3).
4. If the user name is "anonymous" or "ftp", an anonymous ftp account
must be present in the password file (user "ftp"). In this case
the user is allowed to log in by specifying any password (by
convention an email address for the user should be used as the
password).
In the last case, ftpd takes special measures to restrict the
client's access privileges. The server performs a chroot(2) to the
home directory of the "ftp" user. In order that system security is not
breached, it is recommended that the "ftp" subtree be constructed with
care, following these rules:
`~ftp'
Make the home directory owned by "root" and unwritable by anyone.
`~ftp/bin'
Make this directory owned by "root" and unwritable by anyone (mode
555). The program ls(1) must be present to support the list
command. This program should be mode 111.
`~ftp/etc'
Make this directory owned by "root" and unwritable by anyone (mode
555). The files passwd(5) and group(5) must be present for the ls
command to be able to produce owner names rather than numbers.
The password field in passwd is not used, and should not contain
real passwords. The file motd, if present, will be printed after
a successful login. These files should be mode 444.
`~ftp/pub'
Make this directory mode 777 and owned by "ftp". Guests can then
place files which are to be accessible via the anonymous account
in this directory.
Configuration files
===================
``/etc/ftpusers''
List of unwelcome/restricted users.
``/etc/ftpwelcome''
Welcome notice.
``/etc/motd''
Welcome notice after login.
``/etc/nologin''
Displayed and access refused.
File: inetutils.info, Node: inetd, Next: ping, Prev: ftpd, Up: Top
inetd
*****
`Inetd' program should be run at boot time by /etc/rc (see rc(8)).
It then listens for connections on certain internet sockets. When a
connection is found on one of its sockets, it decides what service the
socket corresponds to, and invokes a program to service the request.
The server program is invoked with the service socket as its standard
input, output and error descriptors. After the program is finished,
inetd continues to listen on the socket (except in some cases which
will be described below). Essentially, inetd allows running one daemon
to invoke several others, reducing load on the system.
Invoking
========
The options are as follows:
`-d'
`--debug'
Turns on debugging.
`-R RATE'
`--rate=RATE'
Specifies the maximum number of times a service can be invoked in
one minute; the default is 1000.
Configuration file
==================
Upon execution, inetd reads its configuration information from a
configuration pathnames on the command line, by default,
`/etc/inetd.conf' and `/etc/initd.d'. If the configuration pathname is
a directory, all the files in the directory are read like a
configuration file. All of the configuration files are read and merged.
There must be an entry for each field in the configuration file, with
entries for each field separated by a tab or a space. Comments are
denoted by a "#" at the beginning of a line. There must be an entry
for each field. The fields of the configuration file are as follows:
service name
socket type
protocol
wait/nowait
user
server program
server program arguments
There are two types of services that inetd can start: standard and
TCPMUX. A standard service has a well-known port assigned to it; it
may be a service that implements an official Internet standard or is a
BSD-specific service. As described in RFC 1078, TCPMUX services are
nonstandard services that do not have a well-known port assigned to
them. They are invoked from inetd when a program connects to the
"tcpmux" well-known port and specifies the service name. This feature
is useful for adding locally-developed servers.
The service-name entry is the name of a valid service in the file
`/etc/services'. For "internal" services (discussed below), the service
name must be the official name of the service (that is, the first entry
in `/etc/services'). For TCPMUX services, the value of the service-name
field consists of the string "tcpmux" followed by a slash and the
locally-chosen service name. The service names listed in /etc/services
and the name "help" are reserved. Try to choose unique names for your
TCPMUX services by prefixing them with your organization's name and
suffixing them with a version number.
The socket-type should be one of "stream", "dgram", "raw", "rdm", or
"seqpacket", depending on whether the socket is a stream, datagram,
raw, reliably delivered message, or sequenced packet socket. TCPMUX
services must use "stream".
The protocol must be a valid protocol as given in /etc/protocols.
Examples might be "tcp" or "udp". TCPMUX services must use "tcp".
The wait/nowait entry specifies whether the server that is invoked
by inetd will take over the socket associated with the service access
point, and thus whether inetd should wait for the server to exit before
listening for new service requests. Datagram servers must use "wait",
as they are always invoked with the original datagram socket bound to
the specified service address. These servers must read at least one
datagram from the socket before exiting. If a datagram server connects
to its peer, freeing the socket so inetd can received further messages
on the socket, it is said to be a "multi-threaded" server; it should
read one datagram from the socket and create a new socket connected to
the peer. It should fork, and the parent should then exit to allow
inetd to check for new service requests to spawn new servers. Datagram
servers which process all incoming datagrams on a socket and eventually
time out are said to be "single-threaded". Comsat(8), (biff(1)) and
talkd(8) are both examples of the latter type of datagram server.
Tftpd(8) is an example of a multi-threaded datagram server.
Servers using stream sockets generally are multi-threaded and use the
"nowait" entry. Connection requests for these services are accepted by
inetd, and the server is given only the newly-accepted socket connected
to a client of the service. Most stream-based services operate in this
manner. Stream-based servers that use "wait" are started with the
listening service socket, and must accept at least one connection
request before exiting. Such a server would normally accept and
process incoming connection requests until a timeout. TCPMUX services
must use "nowait".
The user entry should contain the user name of the user as whom the
server should run. This allows for servers to be given less permission
than root.
The server-program entry should contain the pathname of the program
which is to be executed by inetd when a request is found on its socket.
If inetd provides this service internally, this entry should be
"internal".
The server program arguments should be just as arguments normally
are, starting with argv[0], which is the name of the program. If the
service is provided internally, the word "internal" should take the
place of this entry.
The inetd program provides several "trivial" services internally by
use of routines within itself. These services are "echo", "discard",
"chargen" (character generator), "daytime" (human readable time), and
"time" (machine readable time, in the form of the number of seconds
since midnight, January 1, 1900). All of these services are tcp based.
For details of these services, consult the appropriate RFC from the
Network Information Center.
The inetd program rereads its configuration file when it receives a
hangup signal, SIGHUP. Services may be added, deleted or modified when
the configuration file is reread.
TCPMUX
======
RFC 1078 describes the TCPMUX protocol: "A TCP client connects to a
foreign host on TCP port 1. It sends the service name followed by a
carriage-return line-feed <CRLF>. The service name is never case
sensitive. The server replies with a single character indicating
positive (+) or negative (-) acknowledgment, immediately followed by an
optional message of explanation, terminated with a <CRLF>. If the
reply was positive, the selected protocol begins; otherwise the
connection is closed." The program is passed the TCP connection as
file descriptors 0 and 1.
If the TCPMUX service name begins with a "+", inetd returns the
positive reply for the program. This allows you to invoke programs
that use stdin/stdout without putting any special server code in them.
The special service name "help" causes inetd to list TCPMUX services
in `inetd.conf'.
Here are several example service entries for the various types of
services:
ftp stream tcp nowait root /usr/libexec/ftpd ftpd -l
ntalk dgram udp wait root /usr/libexec/ntalkd ntalkd
tcpmux/+date stream tcp nowait guest /bin/date date
tcpmux/phonebook stream tcp nowait guest /usr/bin/phonebook phonebook
Error Messages
==============
The inetd server logs error messages using syslog(3). Important
error messages and their explanations are:
`service/protocol server failing (looping), service terminated.'
The number of requests for the specified service in the past
minute exceeded the limit. The limit exists to prevent a broken
program or a malicious user from swamping the system. This
message may occur for several reasons: 1) there are lots of hosts
requesting the service within a short time period, 2) a 'broken'
client program is requesting the service too frequently, 3) a
malicious user is running a program to invoke the service in a
'denial of service' attack, or 4) the invoked service program has
an error that causes clients to retry quickly. Use the [-R]
option, as described above, to change the rate limit. Once the
limit is reached, the service will be reenabled automatically in
10 minutes.
`service/protocol: No such user 'user', service ignored'
`service/protocol: getpwnam: user: No such user'
No entry for user exists in the passwd file. The first message
occurs when inetd (re)reads the configuration file. The second
message occurs when the service is invoked. the service will be
reenabled automatically in 10 minutes.
`service/protocol: No such user 'user', service ignored'
`service/protocol: getpwnam: user: No such user'
No entry for user exists in the passwd file. The first message
occurs when inetd (re)reads the configuration file. The second
message occurs when the service is invoked.
`service: can't set uid number'
`service: can't set gid number'
The user or group ID for the entry's user is invalid.
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