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: ping, Next: rcp, Prev: inetd, Up: Top
ping
****
`Ping' uses the ICMP protocol's mandatory ECHO_REQUEST datagram to
elicit an ICMP ECHO_RESPONSE from a host or gateway. ECHO_REQUEST
datagrams ("pings") have an IP and ICMP header, followed by a "struct
timeval" and then an arbitrary number of "pad" bytes used to fill out
the packet.
Invoking
========
The options are as follows:
`--echo'
Send ICMP_ECHO requests (default).
`--address'
Send ICMP_ADDRESS packets.
`--timestamp'
Send ICMP_TIMESTAMP packets.
`--router'
Send ICMP_ROUTERDISCOVERY packets.
`-c N'
`--count=N'
Stop after sending (and receiving) count ECHO_RESPONSE packets.
`-d'
`-debug'
Set the SO_DEBUG option on the socket being used.
`-i N'
`--interval=N'
Wait N seconds between sending each packet. The default is to wait
for one second between each packet. This option is incompatible
with the -f option.
`-n'
`--numeric'
Numeric output only. No attempt will be made to lookup symbolic
names for host addresses.
`-r'
`--ignore-routing'
Bypass the normal routing tables and send directly to a host on an
attached network. If the host is not on a directly-attached
network, an error is returned. This option can be used to ping a
local host through an interface that has no route through it
(e.g., after the interface was dropped by routed(8)).
`-v'
`--verbose'
Verbose output. ICMP packets other than ECHO_RESPONSE that are
received are listed.
`-f'
`--flood'
Flood ping. Outputs packets as fast as they come back or one
hundred times per second, whichever is more. For every
ECHO_REQUEST sent a period "." is printed, while for every
ECHO_REPLY received a backspace is printed. This provides a rapid
display of how many packets are being dropped. Only the
super-user may use this option. This can be very hard on a network
and should be used with caution.
`-l N'
`--preload=N'
If N is specified, ping sends that many packets as fast as
possible before falling into its normal mode of behavior.
`-p PAT'
`--pattern=PAT'
You may specify up to 16 "pad" bytes to fill out the packet you
send. This is useful for diagnosing data-dependent problems in a
network. For example, "-p ff" will cause the sent packet to be
filled with all ones.
`-q'
`--quiet'
Quiet output. Nothing is displayed except the summary lines at
startup time and when finished.
`-R'
`--route'
Record route. Includes the RECORD_ROUTE option in the
ECHO_REQUEST packet and displays the route buffer on returned
packets. Note that the IP header is only large enough for nine
such routes. Many hosts ignore or discard this option.
`-s N'
`--size=N'
Specifies the number of data bytes to be sent. The default is 56,
which translates into 64 ICMP data bytes when combined with the 8
bytes of ICMP header data.
When using ping for fault isolation, it should first be run on the
local host, to verify that the local network interface is up and
running. Then, hosts and gateways further and further away should be
"pinged". Round-trip times and packet loss statistics are computed.
If duplicate packets are received, they are not included in the packet
loss calculation, although the round trip time of these packets is used
in calculating the minimum/average/maximum round-trip time numbers.
When the speci- fied number of packets have been sent (and received) or
if the program is terminated with a SIGINT, a brief summary is
displayed.
This program is intended for use in network testing, measurement and
man- agement. Because of the load it can impose on the network, it is
unwise to use ping during normal operations or from automated scripts.
ICMP Packet Details
===================
An IP header without options is 20 bytes. An ICMP ECHO_REQUEST
packet contains an additional 8 bytes worth of ICMP header followed by
an arbitrary amount of data. When a packetsize is given, this
indicated the size of this extra piece of data (the default is 56).
Thus the amount of data received inside of an IP packet of type ICMP
ECHO_REPLY will always be 8 bytes more than the requested data space
(the ICMP header).
If the data space is at least eight bytes large, ping uses the first
eight bytes of this space to include a timestamp which it uses in the
computation of round trip times. If less than eight bytes of pad are
specified, no round trip times are given.
Duplicate And Damaged Packets
=============================
Ping will report duplicate and damaged packets. Duplicate packets
should never occur, and seem to be caused by inappropriate link-level
retransmissions. Duplicates may occur in many situations and are rarely
(if ever) a good sign, although the presence of low levels of
duplicates may not always be cause for alarm.
Damaged packets are obviously serious cause for alarm and often
indicate broken hardware somewhere in the ping packet's path (in the
network or in the hosts).
Trying Different Data Patterns
==============================
The (inter)network layer should never treat packets differently
depending on the data contained in the data portion. Unfortunately,
data-dependent problems have been known to sneak into networks and
remain undetected for long periods of time. In many cases the
particular pattern that will have problems is something that doesn't
have sufficient "transitions", such as all ones or all zeros, or a
pattern right at the edge, such as almost all zeros. It isn't
necessarily enough to specify a data pattern of all zeros (for example)
on the command line because the pattern that is of interest is at the
data link level, and the relationship between what you type and what
the controllers transmit can be complicated.
This means that if you have a data-dependent problem you will
probably have to do a lot of testing to find it. If you are lucky, you
may manage to find a file that either can't be sent across your network
or that takes much longer to transfer than other similar length files.
You can then examine this file for repeated patterns that you can test
using the -p option of ping.
TTL Details
===========
The TTL value of an IP packet represents the maximum number of IP
routers that the packet can go through before being thrown away. In
current practice you can expect each router in the Internet to
decrement the TTL field by exactly one.
The TCP/IP specification states that the TTL field for TCP packets
should be set to 60, but many systems use smaller values (4.3 BSD uses
30, 4.2 used 15).
The maximum possible value of this field is 255, and most Unix
systems set the TTL field of ICMP ECHO_REQUEST packets to 255. This is
why you will find you can "ping" some hosts, but not reach them with
telnet(1) or ftp(1).
In normal operation ping prints the ttl value from the packet it
receives. When a remote system receives a ping packet, it can do one of
three things with the TTL field in its response:
*
Not change it; this is what Berkeley Unix systems did before the
4.3BSD-Tahoe release. In this case the TTL value in the received
packet will be 255 minus the number of routers in the round-trip
path.
*
Set it to 255; this is what current Berkeley Unix systems do. In
this case the TTL value in the received packet will be 255 minus
the number of routers in the path from the remote system to the
pinging host.
*
Set it to some other value. Some machines use the same value for
ICMP packets that they use for TCP packets, for example either 30
or 60. Others may use completely wild values.
Many Hosts and Gateways ignore the RECORD_ROUTE option.
The maximum IP header length is too small for options like
RECORD_ROUTE to be completely useful. There's not much that that can
be done about this, however.
Flood pinging is not recommended in general, and flood pinging the
broadcast address should only be done under very controlled conditions.
File: inetutils.info, Node: rcp, Next: rexecd, Prev: ping, Up: Top
rcp
***
`Rcp' copies files between machines. Each file or directory
argument is either a remote file name of the form "rname@rhost:path",
or a local file name (containing no `:' characters, or a `/' before any
`:'s).
Invoking
========
The options are as follows :
`-K'
`--kerberos'
Turns off all Kerberos authentication.
`-k'
`--realm=REALM'
The option requests rcp to obtain tickets for the remote host in
REALM realm instead of the remote host's realm as determined by
krb_realmofhost(3).
`-p'
`--preserve'
Causes rcp to attempt to preserve (duplicate) in its copies the
modification times and modes of the source files, ignoring the
umask. By default, the mode and owner of file2 are preserved if it
already existed; otherwise the mode of the source file modified by
the umask(2) on the destination host is used.
`-r'
`--recursive'
If any of the source files are directories, rcp copies each subtree
rooted at that name; in this case the destination must be a
directory.
`-x'
`--encrypt'
Turns on DES encryption for all data passed via the rcp session.
This may impact response time and CPU utilization, but provides
increased security.
`rcp' doesn't detect all cases where the target of a copy might be a
file in cases where only a directory should be legal.
Is confused by any output generated by commands in a .login,
.profile, or .cshrc file on the remote host.
The destination user and hostname may have to be specified as
"rhost.rname" when the destination machine is running the 4.2BSD version
of `rcp'.
File: inetutils.info, Node: rexecd, Next: rlogin, Prev: rcp, Up: Top
rexecd
******
`Rexecd' is the server for the rexec(3) routine. The server provides
remote execution facilities with authentication based on user names and
passwords.
`Rexecd' listens for service requests at the port indicated in the
"exec" service specification; see services(5). When a service request
is received the following protocol is initiated:
1. The server reads characters from the socket up to a NUL (`\0')
byte. The resultant string is interpreted as an ASCII number,
base 10.
2. If the number received in step 1 is non-zero, it is interpreted as
the port number of a secondary stream to be used for the stderr. A
second connection is then created to the specified port on the
client's machine.
3. A NUL terminated user name of at most 16 characters is retrieved on
the initial socket.
4. A NUL terminated, unencrypted password of at most 16 characters is
retrieved on the initial socket.
5. A NUL terminated command to be passed to a shell is retrieved on
the initial socket. The length of the command is limited by the
upper bound on the size of the system's argument list.
6. `Rexecd' then validates the user as is done at login time and, if
the authentication was successful, changes to the user's home
directory, and establishes the user and group protections of the
user. If any of these steps fail the connection is aborted with a
diagnostic message returned.
7. A NUL byte is returned on the initial socket and the command line
is passed to the normal login shell of the user. The shell
inherits the network connections established by rexecd.
Diagnostics
===========
Except for the last one listed below, all diagnostic messages are
returned on the initial socket, after which any network connections are
closed. An error is indicated by a leading byte with a value of 1 (0
is returned in step 7 above upon successful completion of all the steps
prior to the command execution).
`username too long'
The name is longer than 16 characters.
`password too long'
The password is longer than 16 characters.
`command too long'
The command line passed exceeds the size of the argument list (as
configured into the system).
`Login incorrect.'
No password file entry for the user name existed.
`Password incorrect.'
The wrong password was supplied.
`No remote directory.'
The chdir command to the home directory failed.
`Try again.'
A fork by the server failed.
`<shellname>: ...'
The user's login shell could not be started. This message is
returned on the connection associated with the stderr, and is not
Indicating "Login incorrect" as opposed to "Password incorrect" is a
security breach which allows people to probe a system for users with
null passwords.
File: inetutils.info, Node: rlogin, Next: rlogind, Prev: rexecd, Up: Top
rlogin
******
`rlogin' command logs into a specified remote host and connects your
local terminal to the remote host. The remote terminal type is the
same as that given in the _TERM_ local environment variable. The
terminal or window size is also the same, if the remote host supports
them, and any changes in size are transferred.
When using the `rlogin' command, you can create a link to your path
using a host name as the link name. For example:
#
# ln -s /usr/bin/rlogin HostName
# Hostname -8
Using HOSTNAME automatically uses the `rlogin' to log in to the
remote host named HOSTNAME.
`rlogin' allows access to the remote host without the use of a
passwd. For details, *Note rcmd: (libc)rcmd.
Invoking
========
The options are as follows :
`-8'
`--8-bit'
Allows an eight-bit input data path at all times; otherwise parity
bits are stripped except when the remote side's stop and start
characters are other than ^S/^Q .
`-E'
`--no-escape'
`--no-escape'
Stops any character from being recognized as an escape character.
When used with the -8 option, this provides a completely
transparent connection.
`-K'
`--kerberos'
Turns off all Kerberos authentication.
`-d'
`--debug'
Turns on socket debugging (see setsockopt(2)) on the TCP sockets
used for communication with the remote host.
`-e'
`--escape=CHAR'
Allows user specification of the escape character, which is "~" by
default. This specification may be as a literal character, or as
an octal value in the form \nnn.
`-k'
`--realm=REALM'
The option requests rlogin to obtain tickets for the remote host
in REALM realm instead of the remote host's realm as determined by
krb_realmofhost(3).
`-x'
`--encrypt'
Turns on DES encryption for all data passed via the rlogin
session. This may impact response time and CPU utilization, but
provides increased security.
A line of the form "<escape char>." disconnects from the remote host.
Similarly, the line "<escape char>^Z" will suspend the rlogin session,
and "<escape char><delayed-suspend char>" suspends the send portion of
the rlogin, but allows output from the remote system. By default, the
tilde ("~") character is the escape character, and normally control-Y
("^Y") is the delayed-suspend character.
All echoing takes place at the remote site, so that (except for
delays) the rlogin is transparent. Flow control via ^S/^Q, if
supported, stop and start the flow of information, flushing of input
and output on interrupts are handled properly.
On the server side the iruserok() and ruserok() functions are used to
authenticate see the appropriate man page for more information, if
supported.
Kerberos Authentication
=======================
If `rlogin' was compiled with kerberos support, optins -x, -k, -K
are available. Each user may have a private authorization list in the
file .klogin in their home directory. Each line in this file should
contain a Kerberos principal name of the form principal.instance@realm.
If the originating user is authenticated to one of the principals named
in .klogin, access is granted to the account. The principal
accountname.@localrealm is granted access if there is no .klogin file.
Otherwise a login and password will be prompted for on the remote
machine as in login(1). To avoid certain security problems, the
.klogin file must be owned by the remote user. If Kerberos
authentication fails, a warning message is printed and the standard
Berkeley rlogin is used instead.
File: inetutils.info, Node: rlogind, Next: rsh, Prev: rlogin, Up: Top
rlogind
*******
`rlogind' is the server for the rlogin(1) program. The server
provides a remote login facility with authentication based on
privileged port numbers from trusted hosts.
`Rlogind' listens for service requests at the port indicated in the
"login" service specification; see services(5). When a service request
is received the following protocol is initiated:
1. The server checks the client's source port. If the port is not in
the range 512-1023, the server aborts the connection.
2. The server checks the client's source address and requests the
corresponding host name (see gethostbyaddr(3), hosts(5) and
named(8)). If the hostname cannot be determined, the dot-notation
representation of the host address is used. If the hostname is in
the same domain as the server (according to the last two
components of the domain name), or if the -a option is given, the
addresses for the hostname are requested, verifying that the name
and address correspond. Normal authentication is bypassed if the
address verification fails.
Once the source port and address have been checked, rlogind proceeds
with the authentication process described in rshd(8). It then
allocates a pseudo terminal (see pty(4)), and manipulates file
descriptors so that the slave half of the pseudo terminal becomes the
stdin, stdout, and stderr for a login process. The login process is an
instance of the login(1) program, invoked with the -f option if
authentication has succeeded. If automatic authentication fails, the
user is prompted to log in as if on a standard terminal line.
The parent of the login process manipulates the master side of the
pseudo terminal, operating as an intermediary between the login process
and the client instance of the rlogin program. In normal operation,
the packet protocol described in pty(4) is invoked to provide `^S/^Q'
type facilities and propagate interrupt signals to the remote programs.
The login process propagates the client terminal's baud rate and
terminal type, as found in the environment variable, `TERM'; see
environ(7). The screen or window size of the terminal is requested
from the client, and window size changes from the client are propagated
to the pseudo terminal.
Transport-level keepalive messages are enabled unless the -n option
is client instance of the rlogin program. In normal operation, the
packet protocol described in pty(4) is invoked to provide `^S/^Q' type
facilities and propagate interrupt signals to the remote programs. The
login process propagates the client terminal's baud rate and terminal
type, as found in the environment variable, `TERM'; see environ(7).
The screen or window size of the terminal is requested from the client,
and window size changes from the client are propagated to the pseudo
terminal.
Transport-level keepalive messages are enabled unless the -n option
is present. The use of keepalive messages allows sessions to be timed
out if the client crashes or becomes unreachable.
*Note ruserok: (libc)ruserok, for details.
Invoking
========
The options are as follows :
`-a'
`--verify-hostname'
Ask hostname for verification.
`-d'
`--daemon'
Daemon mode.
`-l'
`--no-rhosts'
Ignore .rhosts file.
`-L'
`--local-domain=NAME'
Set local domain name.
`-n'
`--no-keepalive'
Do not set SO_KEEPALIVE.
`-k'
`--kerberos'
Use kerberos IV authentication.
`-x'
`--encrypt'
Turns on DES encryption for all data passed via the rlogind
session. This may impact response time and CPU utilization, but
provides increased security.
`-D'
`--debug[=LEVEL]'
Set debug level, not implemented.
`-h'
`--help'
Display usage instructions.
`-V'
`--version'
Display program version.
`-o'
`--allow-root'
Allow uid == 0 to login, disable by default\n"
`-p'
`--port=PORT'
Listen on given port (valid only in daemon mode).
`-r'
`--reverse-required'
Required Require reverse resolving of a remote host IP.
Diagnostics
===========
All initial diagnostic messages are indicated by a leading byte with
a value of 1, after which any network connections are closed. If there
are no errors before login is invoked, a null byte is returned as in
indication of success.
`Try again.'
A fork by the server failed.
The authentication procedure used here assumes the integrity of each
client machine and the connecting medium. This is insecure, but is
useful in an "open" environment.
File: inetutils.info, Node: rsh, Next: rshd, Prev: rlogind, Up: Top
rsh
***
`Rsh' executes command on host and copies its standard input to the
remote command, the standard output of the remote command to its
standard output, and the standard error of the remote command to its
standard error. Interrupt, quit and terminate signals are propagated
to the remote command; `rsh' normally terminates when the remote
command does.
When using the `rsh' command, you can create a link to your path
using a host name as the link name. For example:
#
# ln -s /usr/bin/rsh HostName
# Hostname ls
HOSTNAME will be passed to `rsh' as the default host.
`rsh' allows access to the remote host without the use of a passwd.
For details, *Note rcmd: (libc)rcmd.
Invoking
========
The options are as follows :
`-K'
`--kerberos'
Turns off all Kerberos authentication.
`-d'
`--debug'
Turns on socket debugging (see setsockopt(2)) on the TCP sockets
used for communication with the remote host.
`-k'
`--realm=REALM'
The option requests rsh to obtain tickets for the remote host in
REALM realm instead of the remote host's realm as determined by
krb_realmofhost(3).
`-x'
`--encrypt'
Turns on DES encryption for all data passed via the rsh session.
This may impact response time and CPU utilization, but provides
increased security.
`-l'
`--user'
By default, the remote username is the same as the local username.
The -l option or the username@host format allow the remote name to
be specified. Kerberos authentication is used, and authorization
is determined as in rlogin(1).
If no command is specified, you will be logged in on the remote host
using rlogin(1).
Shell metacharacters which are not quoted are interpreted on local
machine, while quoted metacharacters are interpreted on the remote
machine.
For example, the command
# rsh otherhost cat remotefile >> localfile
appends the remote file remotefile to the local file localfile, while
# rsh otherhost cat remotefile ">>" other_remotefile
appends remotefile to other_remotefile.
File: inetutils.info, Node: rshd, Next: logger, Prev: rsh, Up: Top
rshd
****
The `rshd' server is the server for the rcmd(3) routine and,
consequently, for the rsh(1) program. The server provides remote
execution facilities with authentication based on privileged port
numbers from trusted hosts. The `rshd' server listens for service
requests at the port indicated in the "cmd" service specification; see
services(5). When a service request is received the following protocol
is initiated:
1. The server checks the client's source port. If the port is not in
the range 512-1023, the server aborts the connection.
2. The server reads characters from the socket up to a null (`\0')
byte. The resultant string is interpreted as an ASCII number,
base 10.
3. If the number received in step 2 is non-zero, it is interpreted as
the port number of a secondary stream to be used for the stderr. A
second connection is then created to the specified port on the
client's machine. The source port of this second connection is
also in the range 512-1023.
4. The server checks the client's source address and requests the
corresponding host name (see gethostbyaddr(3), hosts(5) and
named(8)). If the hostname cannot be determined, the dot-notation
representation of the host address is used. If the hostname is in
the same domain as the server (according to the last two
components of the domain name), or if the -a option is given, the
addresses for the hostname are requested, verifying that the name
and address correspond. If address verification fails, the
connection is aborted with the message, "Host address mismatch."
5. A null terminated user name of at most 16 characters is retrieved
on the initial socket. This user name is interpreted as the user
identity on the client's machine.
6. A null terminated user name of at most 16 characters is retrieved
on the initial socket. This user name is interpreted as a user
identity to use on the server's machine.
7. A null terminated command to be passed to a shell is retrieved on
the initial socket. The length of the command is limited by the
upper bound on the size of the system's argument list.
8. Rshd then validates the user using ruserok(3), which uses the file
/etc/hosts.equiv and the .rhosts file found in the user's home
directory. The -l option prevents ruserok(3) from doing any
validation based on the user's ".rhosts" file, unless the user is
the superuser.
9. If the file /etc/nologin exists and the user is not the superuser,
the connection is closed.
10. A null byte is returned on the initial socket and the command line
is passed to the normal login shell of the user. The shell
inherits the network connections established by `rshd'.
11. Transport-level keepalive messages are enabled unless the -n
option is present. The use of keepalive messages allows sessions
to be timed out if the client crashes or becomes unreachable.
12. The -L option causes all successful accesses to be logged to
syslogd(8) as auth.info messages.
*Note ruserok: (libc)ruserok, for details.
Invoking
========
The options are as follows :
`-a'
`--verify-hostname'
Ask hostname for verification.
`-l'
`--no-rhosts'
Ignore .rhosts file.
`-L'
`--local-domain=NAME'
Set local domain name.
`-n'
`--no-keepalive'
Do not set SO_KEEPALIVE.
`-k'
`--kerberos'
Use kerberos IV authentication.
`-x'
`--encrypt'
Turns on DES encryption for all data passed via the `rshd' session.
This may impact response time and CPU utilization, but provides
increased security.
`-D'
`--debug[=LEVEL]'
Set debug level, not implemented.
`-h'
`--help'
Display usage instructions.
`-V'
`--version'
Display program version.
Diagnostics
===========
Except for the last one listed below, all diagnostic messages are
returned on the initial socket, after which any network connections are
closed. An error is indicated by a leading byte with a value of 1 (0
is returned in step 10 above upon successful completion of all the
steps prior to the execution of the login shell).
`Locuser too long'
The name of the user on the client's machine is longer than 16
characters.
`Ruser too long'
The name of the user on the remote machine is longer than 16
characters.
`Command too long'
The command line passed exceeds the size of the argument list (as
configured into the system).
`Login incorrect'
No password file entry for the user name existed.
`Remote directory'
The chdir command to the home directory failed.
`Permission denied'
The authentication procedure described above failed.
`Can't make pipe.'
The pipe needed for the stderr, wasn't created.
`Can't fork; try again.'
A fork by the server failed.
`<shellname>: ...'
The user's login shell could not be started. This message is re-
turned on the connection associated with the stderr, and is not
preceded by a flag byte.
The authentication procedure used here assumes the integrity of each
client machine and the connecting medium. This is insecure, but is
useful in an "open" environment.
File: inetutils.info, Node: logger, Next: syslogd, Prev: rshd, Up: Top
logger
******
`logger' is a program to make entries in the system log files. It
provides a shell command interface to the system log module. *Note
Syslog: (libc)Syslog, for details.
The message can contain a priority code, which should be a preceding
decimal number in angle braces, for example, `<5>'. This priority code
should map into the priorities defined in the include file
`<sys/syslog.h>'.
Invoking
========
The options are as follows :
`-i'
Log the process ID of the logger process with each line.
`-s'
Log the message to standard error, as well as the system log. This
option might not be supported on all systems.
`-f FILE'
`--file=FILE'
Log the content of the specified file.
`-p PRIORITY'
`--priority=PRIORITY'
Enter the message with the specified priority. The priority may be
specified numerically or as a `facility.level' pair. For example,
`-p local3.info' logs the message at the informational level in
the `local3' facility. The default is `user.notice'.
The actual list of supported facilities and levels is system
specific.
`-t TAG'
`--tag=TAG'
Mark every line in the log with the specified tag.
The options are followed by the message which should be written to
the log. If not specified, and the -f flag is not provided, standard
input is logged.
The logger utility exits 0 on success, and >0 if an error occurs.
The following examples illustrate the usage of the `logger' command.
logger System rebooted
logger -p local0.notice -t HOSTIDM -f /dev/idmc
File: inetutils.info, Node: syslogd, Next: talk, Prev: logger, Up: Top
syslogd
*******
`syslogd' is a system service that provides error logging facility.
Messages are read from the UNIX domain socket `/dev/log', from an
Internet domain socket specified in `/etc/services', and from the
special device `/dev/klog' (to read kernel messages).
`syslogd' creates the file `/var/run/syslog.pid', and stores its
process id there. This can be used to kill or reconfigure `syslogd'.
The message sent to `syslogd' should consist of a single line. The
message can contain a priority code, which should be a preceding
decimal number in angle braces, for example, `<5>'. This priority code
should map into the priorities defined in the include file
`sys/syslog.h'.
Invoking
========
The options are as follows:
`-f FILE'
`--rcfile=FILE'
Override configuration (the default file is `/etc/syslog.conf').
`--pidfile=FILE'
Override pidfile (the default file is `/var/run/syslogd.pid').
`-n'
`--no-detach'
Do not enter daemon mode.
`-d'
`--debug'
Print debug information (implies `-n').
`-p FILE'
`--socket=FILE'
Override default UNIX domain socket `/dev/log'.
`-a SOCKET'
Add UNIX socket to listen. An unlimited number of sockets is
allowed.
`-r'
`--inet'
Receive remote messages via Internet domain socket.
`--no-unixaf'
Do not listen on UNIX domain sockets (overrides `-a' and `-p').
`--no-klog'
Do not listen to kernel log device `/dev/klog'.
`--no-forward'
Do not forward any messages (overrides `-h').
`-h'
`--hop'
Forward messages from remote hosts.
`-m INTERVAL'
`--mark=INTERVAL'
Specify timestamp interval in logs (0 for no timestamps).
`-l HOSTLIST'
Log hosts in HOSTLIST by their hostname. Multiple lists are
allowed.
`-s DOMAINLIST'
List of domains which should be stripped from the FQDN of hosts
before logging their name. Multiple lists are allowed.
Configuration file
==================
`syslogd' reads its configuration file when it starts up and
whenever it receives a hangup signal. The `syslog.conf' file is the
configuration file for the `syslogd' program. It consists of lines
with two fields: the _selector_ field which specifies the types of
messages and priorities to which the line applies, and an _action_
field which specifies the action to be taken if a message `syslogd'
receives matches the selection criteria. The _selector_ field is
separated from the action field by one or more tab or space characters.
A rule can be splitted in several lines if all lines except the last
are terminated with a backslash `\'.
The Selectors function are encoded as a facility, a period (`.'),
and a level, with no intervening white-space. Both the facility and
the level are case insensitive.
The facility describes the part of the system generating the message,
and is one of the following keywords: `auth', `authpriv', `cron',
`daemon', `kern', `lpr', `mail', `mark', `news', `syslog', `user',
`uucp' and `local0' through `local7'. These keywords (with the
exception of `mark') correspond to the similar `LOG_' values specified
to the `openlog' and `syslog' library routines. *Note Syslog:
(libc)Syslog, for details.
The level describes the severity of the message, and is a keyword
from the following ordered list (higher to lower): `emerg', `alert',
`crit', `err, warning', `notice' and `debug'. These keywords
correspond to the similar `LOG_' values specified to the syslog library
routine.
*Note syslog and vsyslog: (libc)syslog; vsyslog, for a further
descriptions of both the facility and level keywords and their
significance.
If a received message matches the specified facility and is of the
specified level (or a higher level), the action specified in the action
field will be taken.
Multiple selectors may be specified for a single action by separating
them with semicolon (`;') characters. It is important to note,
however, that each selector can modify the ones preceding it.
Multiple facilities may be specified for a single level by separating
them with comma (`,') characters.
An asterisk (`*') can be used to specify all facilities or all
levels. Two asterisks (`**') specifie all facilities not named
previously in the configuration file.
By default, a level applies to all messages with the same or higher
level. The equal (`=') character can be prepended to a level to
restrict this line of the configuration file to messages with the very
same level.
An exclamation mark (`!') prepended to a level or the asterisk means
that this line of the configuration file does not apply to the
specified level (and higher ones). In conjunction with the equal sign,
you can exclude single levels as well.
The special facility _mark_ receives a message at priority `info'
every 20 minutes. This is not enabled by a facility field containing
an asterisk.
The special level `none' disables a particular facility.
The action field of each line specifies the action to be taken when
the selector field selects a message. There are five forms:
* A pathname (beginning with a leading slash). Selected messages are
appended to the file.
You may prepend a minus (`-') to the path to omit syncing the file
after each message log. This can cause data loss at system
crashes, but increases performance for programs which use logging
extensively.
* A named pipe (fifo), beginning with a vertical bar (`|') followed
by a pathname. The pipe must be created with `mkfifo'(8) before
`syslogd' reads its configuration file. This feature is
especially useful fo debugging.
* A hostname (preceded by an at (`@') sign). Selected messages are
forwarded to `syslogd' on the named host.
* A comma separated list of users. Selected messages are written to
those users if they are logged in.
* An asterisk. Selected messages are written to all logged-in users.
Blank lines and lines whose first non-blank character is a hash
(`#') character are ignored.
A configuration file might appear as follows:
# Log all kernel messages, authentication messages of
# level notice or higher and anything of level err or
# higher to the console.
# Don't log private authentication messages!
*.err;kern.*;auth.notice;authpriv.none /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none /var/log/messages
# The authpriv file has restricted access.
authpriv.* /var/log/secure
# Log all the mail messages in one place.
mail.* /var/log/maillog
# Everybody gets emergency messages, plus log them on another
# machine.
*.emerg *
*.emerg @arpa.berkeley.edu
# Root and Eric get alert and higher messages.
*.alert root,eric
# Save mail and news errors of level err and higher in a
# special file.
uucp,news.crit /var/log/spoolerr
The effects of multiple selectors are sometimes not intuitive. For
example `mail.crit,*.err' will select the `mail' facility messages at
the level of `err' or higher, not at the level of `crit' or higher.
File: inetutils.info, Node: talk, Next: talkd, Prev: syslogd, Up: Top
talk
****
`Talk' is a visual communication program which copies lines from
your terminal to that of another user.
Invoking
========
The options are as follows:
`person'
If you wish to talk to someone on your own machine, then person is
just the person's login name. If you wish to talk to a user on
another host, then person is of the form `user@host'.
`ttyname'
If you wish to talk to a user who is logged in more than once, the
ttyname argument may be used to indicate the appropriate terminal
name, where ttyname is of the form `ttyXX'.
When first called, talk sends the message
Message from TalkDaemon@his_machine...
talk: connection requested by your_name@your_machine.
talk: respond with: talk your_name@your_machine
to the user you wish to talk to. At this point, the recipient of the
message should reply by typing
talk your_name@your_machine
It doesn't matter from which machine the recipient replies, as long
as his login-name is the same. Once communication is established, the
two parties may type simultaneously, with their output appearing in
separate windows. Typing control-L `^L' will cause the screen to be
reprinted, while your erase, kill, and word kill characters will behave
normally. To exit, just type your interrupt character; talk then moves
the cursor to the bottom of the screen and restores the terminal to its
previous state.
Permission to talk may be denied or granted by use of the mesg(1)
command. At the outset talking is allowed. Certain commands, in
particular nroff(1) and pr(1), disallow messages in order to prevent
messy output.
To exit, just type your interrupt character; talk then moves the
cursor to the bottom of the screen and restores the terminal to its
previous state.
Permission to talk may be denied or granted by use of the mesg(1)
command. At the outset talking is allowed. Certain commands, in
particular nroff(1) and pr(1), disallow messages in order to prevent
messy output.
The version of talk(1) released with 4.3BSD uses a protocol that is
incompatible with the protocol used in the version released with 4.2BSD.
File: inetutils.info, Node: talkd, Next: tftp, Prev: talk, Up: Top
talkd
*****
`Talkd' is the server that notifies a user that someone else wants to
initiate a conversation. It acts as a repository of invitations,
responding to requests by clients wishing to rendezvous to hold a
conversation. In normal operation, a client, the caller, initiates a
rendezvous by sending a CTL_MSG to the server of type LOOK_UP (see
<protocols/talkd.h>). This causes the server to search its invitation
tables to check if an invitation currently exists for the caller (to
speak to the callee specified in the message). If the lookup fails,
the caller then sends an ANNOUNCE message causing the server to
broadcast an announcement on the callee's login ports requesting
contact. When the callee responds, the local server uses the recorded
invitation to respond with the appropriate rendezvous address and the
caller and callee client programs establish a stream connection through
which the conversation takes place.
Invoking
========
The options are as follows:
`-a FILE'
`--acl=FILE'
Read site-wide ACLs from FILE.
`-d'
`--debug'
Enable debugging.
`-i SECONDS'
`--idle-timeout=SECONDS'
Set idle timeout value.
`-r SECONDS'
`--request-ttl=SECONDS'
Set request time-to-live value.
`-t SECONDS'
`--timeout=SECONDS'
Set timeout value.
File: inetutils.info, Node: tftp, Next: Reporting Bugs, Prev: talkd, Up: Top
tftp
****
`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 may be specified on the command line,
in which case tftp uses host as the default host for future transfers
(see the connect command below).
Invoking
========
tftp [host]
Commands
========
Once tftp is running, it issues the prompt and recognizes the
following commands:
`? command-name ...'
Print help information.
`ascii'
Shorthand for "mode ascii"
`binary'
Shorthand for "mode binary"
`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.
`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.
`trace'
Toggle packet tracing.
`verbose'
Toggle verbose mode.
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.
File: inetutils.info, Node: Reporting Bugs, Next: Concept Index, Prev: tftp, Up: Top
Reporting bugs
**************
Email bug reports to <bug-inetutils@gnu.org>. Be sure to include
the word "inetutils" somewhere in the "Subject:" field.
``syslogd''
The effects of multiple selectors are sometimes not intuitive.
For exam- ple "mail.crit,*.err" will select "mail" facility
messages at the level of "err" or higher, not at the level of
"crit" or higher.
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