X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/6a17f9c26618db5e9592adabbd53c0d5729c63ea..5f4fdfae1aad347ce0a5e84495b7db5f38b3798b:/ssh.1

diff --git a/ssh.1 b/ssh.1
index 31e4c6db..ab36f13f 100644
--- a/ssh.1
+++ b/ssh.1
@@ -24,7 +24,7 @@
 .Op Ar command
 .Pp
 .Nm ssh
-.Op Fl afgknqtvxCPX
+.Op Fl afgknqtvxCPX46
 .Op Fl c Ar blowfish | 3des
 .Op Fl e Ar escape_char
 .Op Fl i Ar identity_file
@@ -33,16 +33,16 @@
 .Op Fl p Ar port
 .Oo Fl L Xo
 .Sm off
-.Ar host :
 .Ar port :
+.Ar host :
 .Ar hostport
 .Sm on
 .Xc
 .Oc
 .Oo Fl R Xo
 .Sm off
-.Ar host :
 .Ar port :
+.Ar host :
 .Ar hostport
 .Sm on
 .Xc
@@ -66,7 +66,7 @@ his/her identity to the remote machine using one of several methods.
 First, if the machine the user logs in from is listed in
 .Pa /etc/hosts.equiv
 or
-.Pa /etc/ssh/shosts.equiv
+.Pa /etc/shosts.equiv
 on the remote machine, and the user names are
 the same on both sides, the user is immediately permitted to log in.
 Second, if 
@@ -89,10 +89,10 @@ means that if the login would be permitted by
 .Pa \&.shosts ,
 .Pa /etc/hosts.equiv ,
 or
-.Pa /etc/ssh/shosts.equiv ,
+.Pa /etc/shosts.equiv ,
 and if additionally the server can verify the client's
 host key (see 
-.Pa /etc/ssh/ssh_known_hosts
+.Pa /etc/ssh_known_hosts
 and
 .Pa $HOME/.ssh/known_hosts
 in the
@@ -250,7 +250,7 @@ identifications for all hosts it has ever been used with.  The
 database is stored in 
 .Pa \&.ssh/known_hosts
 in the user's home directory.  Additionally, the file 
-.Pa /etc/ssh/ssh_known_hosts
+.Pa /etc/ssh_known_hosts
 is automatically checked for known hosts.  Any new hosts are
 automatically added to the user's file.  If a host's identification
 ever changes,
@@ -293,7 +293,7 @@ disables any escapes and makes the session fully transparent.
 .It Fl f
 Requests
 .Nm
-to go to background after authentication.  This is useful
+to go to background just before command execution.  This is useful
 if
 .Nm
 is going to ask for passwords or passphrases, but the user
@@ -302,6 +302,8 @@ wants it in the background.  This implies
 The recommended way to start X11 programs at a remote site is with
 something like
 .Ic ssh -f host xterm .
+.It Fl g
+Allows remote hosts to connect to local forwarded ports.
 .It Fl i Ar identity_file
 Selects the file from which the identity (private key) for 
 RSA authentication is read.  Default is 
@@ -312,8 +314,6 @@ multiple
 .Fl i
 options (and multiple identities specified in
 configuration files).
-.It Fl g
-Allows remote hosts to connect to local forwarded ports.
 .It Fl k
 Disables forwarding of Kerberos tickets and AFS tokens. This may
 also be specified on a per-host basis in the configuration file.
@@ -351,7 +351,7 @@ per-host basis in the configuration file.
 Use a non-privileged port for outgoing connections.
 This can be used if your firewall does
 not permit connections from privileged ports.
-Note that this option turns of
+Note that this option turns off
 .Cm RhostsAuthentication
 and
 .Cm RhostsRSAAuthentication .
@@ -378,7 +378,9 @@ Enables X11 forwarding.
 .It Fl C
 Requests compression of all data (including stdin, stdout, stderr, and
 data for forwarded X11 and TCP/IP connections).  The compression
-algorithm is the same used by gzip, and the
+algorithm is the same used by
+.Xr gzip 1 ,
+and the
 .Dq level
 can be controlled by the
 .Cm CompressionLevel
@@ -396,9 +398,13 @@ by allocating a socket to listen to
 on the local side, and whenever a connection is made to this port, the
 connection is forwarded over the secure channel, and a connection is
 made to
-.Ar host:hostport
+.Ar host
+port
+.Ar hostport
 from the remote machine.  Port forwardings can also be specified in the
 configuration file.  Only root can forward privileged ports.
+IPv6 addresses can be specified with an alternative syntax:
+.Ar port/host/hostport
 .It Fl R Ar port:host:hostport
 Specifies that the given port on the remote (server) host is to be
 forwarded to the given host and port on the local side.  This works
@@ -407,10 +413,20 @@ by allocating a socket to listen to
 on the remote side, and whenever a connection is made to this port, the
 connection is forwarded over the secure channel, and a connection is
 made to
-.Ar host:hostport
+.Ar host
+port
+.Ar hostport
 from the local machine.  Port forwardings can also be specified in the
 configuration file.  Privileged ports can be forwarded only when
 logging in as root on the remote machine.
+.It Fl 4
+Forces
+.Nm
+to use IPv4 addresses only.
+.It Fl 6
+Forces
+.Nm
+to use IPv6 addresses only.
 .El
 .Sh CONFIGURATION FILES
 .Nm
@@ -418,7 +434,7 @@ obtains configuration data from the following sources (in this order):
 command line options, user's configuration file
 .Pq Pa $HOME/.ssh/config ,
 and system-wide configuration file
-.Pq Pa /etc/ssh/ssh_config .
+.Pq Pa /etc/ssh_config .
 For each parameter, the first obtained value
 will be used.  The configuration files contain sections bracketed by
 "Host" specifications, and that section is only applied for hosts that
@@ -472,6 +488,15 @@ user to supply the password.  The argument must be
 .Dq yes
 or
 .Dq no .
+.It Cm CheckHostIP
+If this flag is set to
+.Dq yes ,
+ssh will additionally check the host ip address in the
+.Pa known_hosts
+file. This allows ssh to detect if a host key changed due to DNS spoofing.
+If the option is set to
+.Dq no ,
+the check will not be executed.
 .It Cm Cipher
 Specifies the cipher to use for encrypting the session.  Currently,
 .Dq blowfish ,
@@ -488,7 +513,8 @@ or
 Specifies the compression level to use if compression is enable.  The
 argument must be an integer from 1 (fast) to 9 (slow, best).  The
 default level is 6, which is good for most applications.  The meaning
-of the values is the same as in GNU GZIP.
+of the values is the same as in
+.Xr gzip 1 .
 .It Cm ConnectionAttempts
 Specifies the number of tries (one per second) to make before falling
 back to rsh or exiting.  The argument must be an integer.  This may be
@@ -542,7 +568,7 @@ The default is
 .Dq no .
 .It Cm GlobalKnownHostsFile
 Specifies a file to use instead of 
-.Pa /etc/ssh/ssh_known_hosts .
+.Pa /etc/ssh_known_hosts .
 .It Cm HostName
 Specifies the real host name to log into.  This can be used to specify
 nicnames or abbreviations for hosts.  Default is the name given on the
@@ -596,12 +622,6 @@ first argument must be a port number, and the second must be
 host:port.  Multiple forwardings may be specified, and additional
 forwardings can be given on the command line.  Only the root can
 forward privileged ports.
-.It Cm PasswordAuthentication
-Specifies whether to use password authentication.  The argument to
-this keyword must be
-.Dq yes
-or
-.Dq no .
 .It Cm LogLevel
 Gives the verbosity level that is used when logging messages from
 .Nm ssh .
@@ -611,6 +631,12 @@ The default is INFO.
 .It Cm NumberOfPasswordPrompts
 Specifies the number of password prompts before giving up. The
 argument to this keyword must be an integer. Default is 3.
+.It Cm PasswordAuthentication
+Specifies whether to use password authentication.  The argument to
+this keyword must be
+.Dq yes
+or
+.Dq no .
 .It Cm Port
 Specifies the port number to connect on the remote host.  Default is
 22.
@@ -627,6 +653,9 @@ server running on some machine, or execute
 somewhere.  Host key management will be done using the
 HostName of the host being connected (defaulting to the name typed by
 the user).
+Note that
+.Cm CheckHostIP
+is not available for connects with a proxy command.
 .Pp
 .It Cm RemoteForward
 Specifies that a TCP/IP port on the remote machine be forwarded over
@@ -662,15 +691,16 @@ or
 RSA authentication will only be
 attempted if the identity file exists, or an authentication agent is
 running.
-.It Cm CheckHostIP
-If this flag is set to
-.Dq yes ,
-ssh will additionally check the host ip address in the
-.Pa known_hosts
-file. This allows ssh to detect if a host key changed due to DNS spoofing.
-If the option is set to
-.Dq no ,
-the check will not be executed.
+.It Cm SkeyAuthentication
+Specifies whether to use
+.Xr skey 1
+authentication.  The argument to
+this keyword must be
+.Dq yes
+or
+.Dq no .
+The default is
+.Dq no .
 .It Cm StrictHostKeyChecking
 If this flag is set to
 .Dq yes , 
@@ -680,7 +710,7 @@ ssh will never automatically add host keys to the
 file, and refuses to connect hosts whose host key has changed.  This
 provides maximum protection against trojan horse attacks.  However, it
 can be somewhat annoying if you don't have good
-.Pa /etc/ssh/ssh_known_hosts
+.Pa /etc/ssh_known_hosts
 files installed and frequently
 connect new hosts.  Basically this option forces the user to manually
 add any new hosts.  Normally this option is disabled, and new hosts
@@ -690,13 +720,6 @@ argument must be
 .Dq yes
 or
 .Dq no .
-.It Cm User
-Specifies the user to log in as.  This can be useful if you have a
-different user name in different machines.  This saves the trouble of
-having to remember to give the user name on the command line.
-.It Cm UserKnownHostsFile
-Specifies a file to use instead of
-.Pa $HOME/.ssh/known_hosts .
 .It Cm UsePrivilegedPort
 Specifies whether to use a privileged port for outgoing connections.
 The argument must be
@@ -707,10 +730,17 @@ The default is
 .Dq yes .
 Note that setting this option to
 .Dq no
-turns of
+turns off
 .Cm RhostsAuthentication
 and
 .Cm RhostsRSAAuthentication .
+.It Cm User
+Specifies the user to log in as.  This can be useful if you have a
+different user name in different machines.  This saves the trouble of
+having to remember to give the user name on the command line.
+.It Cm UserKnownHostsFile
+Specifies a file to use instead of
+.Pa $HOME/.ssh/known_hosts .
 .It Cm UseRsh
 Specifies that rlogin/rsh should be used for this host.  It is
 possible that the host does not at all support the
@@ -787,15 +817,9 @@ to the environment.
 .It Pa $HOME/.ssh/known_hosts
 Records host keys for all hosts the user has logged into (that are not
 in
-.Pa /etc/ssh/ssh_known_hosts ) .
+.Pa /etc/ssh_known_hosts ) .
 See
 .Xr sshd 8 .
-.It Pa $HOME/.ssh/random_seed
-Used for seeding the random number generator.  This file contains
-sensitive data and should read/write for the user and not accessible
-for others.  This file is created the first time the program is run
-and updated automatically.  The user should never need to read or
-modify this file.
 .It Pa $HOME/.ssh/identity
 Contains the RSA authentication identity of the user.  This file
 contains sensitive data and should be readable by the user but not
@@ -832,7 +856,7 @@ identity files (that is, each line contains the number of bits in
 modulus, public exponent, modulus, and comment fields, separated by
 spaces).  This file is not highly sensitive, but the recommended
 permissions are read/write for the user, and not accessible by others.
-.It Pa /etc/ssh/ssh_known_hosts
+.It Pa /etc/ssh_known_hosts
 Systemwide list of known host keys.  This file should be prepared by the
 system administrator to contain the public host keys of all machines in the
 organization.  This file should be world-readable.  This file contains
@@ -851,7 +875,7 @@ to verify the client host when logging in; other names are needed because
 does not convert the user-supplied name to a canonical name before
 checking the key, because someone with access to the name servers
 would then be able to fool host authentication.
-.It Pa /etc/ssh/ssh_config
+.It Pa /etc/ssh_config
 Systemwide configuration file.  This file provides defaults for those
 values that are not specified in the user's configuration file, and
 for those users who do not have a configuration file.  This file must
@@ -878,7 +902,7 @@ Note that by default
 will be installed so that it requires successful RSA host
 authentication before permitting \s+2.\s0rhosts authentication.  If your
 server machine does not have the client's host key in
-.Pa /etc/ssh/ssh_known_hosts ,
+.Pa /etc/ssh_known_hosts ,
 you can store it in
 .Pa $HOME/.ssh/known_hosts .
 The easiest way to do this is to
@@ -905,13 +929,13 @@ manual page).  If the client host is found in this file, login is
 automatically permitted provided client and server user names are the
 same.  Additionally, successful RSA host authentication is normally
 required.  This file should only be writable by root.
-.It Pa /etc/ssh/shosts.equiv
+.It Pa /etc/shosts.equiv
 This file is processed exactly as 
 .Pa /etc/hosts.equiv .
 This file may be useful to permit logins using
 .Nm
 but not using rsh/rlogin.
-.It Pa /etc/ssh/sshrc
+.It Pa /etc/sshrc
 Commands in this file are executed by
 .Nm
 when the user logs in just before the user's shell (or command) is started.
@@ -926,6 +950,10 @@ started.
 See the 
 .Xr sshd 8
 manual page for more information.
+.It Pa $HOME/.ssh/environment
+Contains additional definitions for environment variables, see section
+.Sx ENVIRONMENT
+above.
 .It Pa libcrypto.so.X.1
 A version of this library which includes support for the RSA algorithm
 is required for proper operation.
@@ -962,6 +990,9 @@ supports one-time password authentication with
 The libraries described in
 .Xr ssl 8
 are required for proper operation.
+.Pp
+OpenSSH has been created by Aaron Campbell, Bob Beck, Markus Friedl,
+Niels Provos, Theo de Raadt, and Dug Song.
 .Sh SEE ALSO
 .Xr rlogin 1 ,
 .Xr rsh 1 ,