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- markus@cvs.openbsd.org 2001/04/22 23:58:36 

[ssh-keygen.1 ssh.1 sshd.8]
     document hostbased and other cleanup
This commit is contained in:
Ben Lindstrom 2001-04-23 13:02:16 +00:00
parent 2857d9cf77
commit c65e6a0fec
4 changed files with 153 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
ChangeLog
View File

@ -1,3 +1,9 @@
20010424
- OpenBSD CVS Sync
- markus@cvs.openbsd.org 2001/04/22 23:58:36
[ssh-keygen.1 ssh.1 sshd.8]
document hostbased and other cleanup
20010422 20010422
- OpenBSD CVS Sync - OpenBSD CVS Sync
- markus@cvs.openbsd.org 2001/04/20 16:32:22 - markus@cvs.openbsd.org 2001/04/20 16:32:22
@ -5225,4 +5231,4 @@
- Wrote replacements for strlcpy and mkdtemp - Wrote replacements for strlcpy and mkdtemp
- Released 1.0pre1 - Released 1.0pre1
$Id: ChangeLog,v 1.1159 2001/04/22 17:19:46 mouring Exp $ $Id: ChangeLog,v 1.1160 2001/04/23 13:02:16 mouring Exp $

6
ssh-keygen.1
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@ -1,4 +1,4 @@
.\" $OpenBSD: ssh-keygen.1,v 1.38 2001/04/22 13:41:02 markus Exp $ .\" $OpenBSD: ssh-keygen.1,v 1.39 2001/04/22 23:58:36 markus Exp $
.\" .\"
.\" -*- nroff -*- .\" -*- nroff -*-
.\" .\"
@ -81,10 +81,10 @@
generates, manages and converts authentication keys for generates, manages and converts authentication keys for
.Xr ssh 1 . .Xr ssh 1 .
.Nm .Nm
defaults to generating a RSA1 key for use by protocols 1.3 and 1.5; defaults to generating a RSA1 key for use by SSH protocol version 1.
specifying the specifying the
.Fl t .Fl t
option allows you to create a key for use by protocol 2.0. option allows you to create a key for use by SSH protocol version 2.
.Pp .Pp
Normally each user wishing to use SSH Normally each user wishing to use SSH
with RSA or DSA authentication runs this once to create the authentication with RSA or DSA authentication runs this once to create the authentication

100
ssh.1
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@ -34,7 +34,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: ssh.1,v 1.106 2001/04/22 13:32:27 markus Exp $ .\" $OpenBSD: ssh.1,v 1.107 2001/04/22 23:58:36 markus Exp $
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSH 1 .Dt SSH 1
.Os .Os
@ -110,7 +110,7 @@ permitted to log in.
This form of authentication alone is normally not This form of authentication alone is normally not
allowed by the server because it is not secure. allowed by the server because it is not secure.
.Pp .Pp
The second (and primary) authentication method is the The second authentication method is the
.Pa rhosts .Pa rhosts
or or
.Pa hosts.equiv .Pa hosts.equiv
@ -205,13 +205,18 @@ the password cannot be seen by someone listening on the network.
.Ss SSH protocol version 2 .Ss SSH protocol version 2
.Pp .Pp
When a user connects using the protocol version 2 When a user connects using the protocol version 2
different authentication methods are available: different authentication methods are available.
At first, the client attempts to authenticate using the public key method. Using the default values for
If this method fails password authentication is tried. .Cm PreferredAuthentications ,
the client will try to authenticate first using the public key method;
if this method fails password authentication is attempted,
and finally if this method fails keyboard-interactive authentication
is attempted.
If this method fails password authentication is
tried.
.Pp .Pp
The public key method is similar to RSA authentication described The public key method is similar to RSA authentication described
in the previous section except that the DSA or RSA algorithm is used in the previous section and allows the RSA or DSA algorithm to be used:
instead.
The client uses his private key, The client uses his private key,
.Pa $HOME/.ssh/id_dsa .Pa $HOME/.ssh/id_dsa
or or
@ -225,8 +230,10 @@ and is only known to the client and the server.
.Pp .Pp
If public key authentication fails or is not available a password If public key authentication fails or is not available a password
can be sent encrypted to the remote host for proving the user's identity. can be sent encrypted to the remote host for proving the user's identity.
This protocol 2 implementation does not yet support Kerberos or .Pp
S/Key authentication. Additionally,
.Nm
supports hostbased or challenge response authentication.
.Pp .Pp
Protocol 2 provides additional mechanisms for confidentiality Protocol 2 provides additional mechanisms for confidentiality
(the traffic is encrypted using 3DES, Blowfish, CAST128 or Arcfour) (the traffic is encrypted using 3DES, Blowfish, CAST128 or Arcfour)
@ -286,7 +293,7 @@ Background ssh
List forwarded connections List forwarded connections
.It Cm ~& .It Cm ~&
Background ssh at logout when waiting for forwarded connection / X11 sessions Background ssh at logout when waiting for forwarded connection / X11 sessions
to terminate (this does not currently work for SSH protocol version 2) to terminate (protocol version 1 only)
.It Cm ~? .It Cm ~?
Display a list of escape characters Display a list of escape characters
.It Cm ~R .It Cm ~R
@ -573,6 +580,8 @@ from the local machine.
Port forwardings can also be specified in the configuration file. Port forwardings can also be specified in the configuration file.
Privileged ports can be forwarded only when Privileged ports can be forwarded only when
logging in as root on the remote machine. logging in as root on the remote machine.
IPv6 addresses can be specified with an alternative syntax:
.Ar port/host/hostport
.It Fl 1 .It Fl 1
Forces Forces
.Nm .Nm
@ -645,6 +654,7 @@ The argument to this keyword must be
.Dq yes .Dq yes
or or
.Dq no . .Dq no .
This option applies to protocol version 1 only.
.It Cm BatchMode .It Cm BatchMode
If set to If set to
.Dq yes , .Dq yes ,
@ -687,8 +697,7 @@ The default is
.Pp .Pp
.Bd -literal .Bd -literal
``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour, ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
aes192-cbc,aes256-cbc,rijndael128-cbc,rijndael192-cbc, aes192-cbc,aes256-cbc''
rijndael256-cbc,rijndael-cbc@lysator.liu.se''
.Ed .Ed
.It Cm Compression .It Cm Compression
Specifies whether to use compression. Specifies whether to use compression.
@ -704,21 +713,13 @@ 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 default level is 6, which is good for most applications.
The meaning of the values is the same as in The meaning of the values is the same as in
.Xr gzip 1 . .Xr gzip 1 .
Note that this option applies to protocol version 1 only.
.It Cm ConnectionAttempts .It Cm ConnectionAttempts
Specifies the number of tries (one per second) to make before falling Specifies the number of tries (one per second) to make before falling
back to rsh or exiting. back to rsh or exiting.
The argument must be an integer. The argument must be an integer.
This may be useful in scripts if the connection sometimes fails. This may be useful in scripts if the connection sometimes fails.
The default is 4. The default is 4.
.It Cm PubkeyAuthentication
Specifies whether to try public key authentication.
The argument to this keyword must be
.Dq yes
or
.Dq no .
The default is
.Dq yes .
Note that this option applies to protocol version 2 only.
.It Cm EscapeChar .It Cm EscapeChar
Sets the escape character (default: Sets the escape character (default:
.Ql ~ ) . .Ql ~ ) .
@ -783,17 +784,29 @@ host key database instead of
Specifies a file to use for the protocol version 2 global Specifies a file to use for the protocol version 2 global
host key database instead of host key database instead of
.Pa /etc/ssh_known_hosts2 . .Pa /etc/ssh_known_hosts2 .
.It Cm HostKeyAlias .It Cm HostbasedAuthentication
Specifies an alias that should be used instead of the Specifies whether to try rhosts based authentication with public key
real host name when looking up or saving the host key authentication.
in the known_hosts files. The argument must be
This option is useful for tunneling ssh connections .Dq yes
or if you have multiple servers running on a single host. or
.Dq no .
The default is
.Dq yes .
This option applies to protocol version 2 only and
is similar to
.Cm RhostsRSAAuthentication .
.It Cm HostKeyAlgorithms .It Cm HostKeyAlgorithms
Specfies the protocol version 2 host key algorithms Specfies the protocol version 2 host key algorithms
that the client wants to use in order of preference. that the client wants to use in order of preference.
The default for this option is: The default for this option is:
.Dq ssh-rsa,ssh-dss .Dq ssh-rsa,ssh-dss
.It Cm HostKeyAlias
Specifies an alias that should be used instead of the
real host name when looking up or saving the host key
in the host key database files.
This option is useful for tunneling ssh connections
or if you have multiple servers running on a single host.
.It Cm HostName .It Cm HostName
Specifies the real host name to log into. Specifies the real host name to log into.
This can be used to specify nicknames or abbreviations for hosts. This can be used to specify nicknames or abbreviations for hosts.
@ -802,7 +815,7 @@ Numeric IP addresses are also permitted (both on the command line and in
.Cm HostName .Cm HostName
specifications). specifications).
.It Cm IdentityFile .It Cm IdentityFile
Specifies the file from which the user's RSA authentication identity Specifies the file from which the user's RSA or DSA authentication identity
is read (default is read (default
.Pa $HOME/.ssh/identity .Pa $HOME/.ssh/identity
in the user's home directory). in the user's home directory).
@ -882,7 +895,6 @@ or
.Dq no . .Dq no .
The default is The default is
.Dq yes . .Dq yes .
Note that this option applies to both protocol version 1 and 2.
.It Cm Port .It Cm Port
Specifies the port number to connect on the remote host. Specifies the port number to connect on the remote host.
Default is 22. Default is 22.
@ -934,6 +946,15 @@ Note that
.Cm CheckHostIP .Cm CheckHostIP
is not available for connects with a proxy command. is not available for connects with a proxy command.
.Pp .Pp
.It Cm PubkeyAuthentication
Specifies whether to try public key authentication.
The argument to this keyword must be
.Dq yes
or
.Dq no .
The default is
.Dq yes .
This option applies to protocol version 2 only.
.It Cm RemoteForward .It Cm RemoteForward
Specifies that a TCP/IP port on the remote machine be forwarded over Specifies that a TCP/IP port on the remote machine be forwarded over
the secure channel to given host:port from the local machine. the secure channel to given host:port from the local machine.
@ -951,13 +972,15 @@ Disabling rhosts authentication may reduce
authentication time on slow connections when rhosts authentication is authentication time on slow connections when rhosts authentication is
not used. not used.
Most servers do not permit RhostsAuthentication because it Most servers do not permit RhostsAuthentication because it
is not secure (see RhostsRSAAuthentication). is not secure (see
.Cm RhostsRSAAuthentication ).
The argument to this keyword must be The argument to this keyword must be
.Dq yes .Dq yes
or or
.Dq no . .Dq no .
The default is The default is
.Dq yes . .Dq yes .
This option applies to protocol version 1 only.
.It Cm RhostsRSAAuthentication .It Cm RhostsRSAAuthentication
Specifies whether to try rhosts based authentication with RSA host Specifies whether to try rhosts based authentication with RSA host
authentication. authentication.
@ -967,6 +990,7 @@ or
.Dq no . .Dq no .
The default is The default is
.Dq yes . .Dq yes .
This option applies to protocol version 1 only.
.It Cm RSAAuthentication .It Cm RSAAuthentication
Specifies whether to try RSA authentication. Specifies whether to try RSA authentication.
The argument to this keyword must be The argument to this keyword must be
@ -1037,13 +1061,13 @@ or
.Dq no . .Dq no .
The default is The default is
.Dq no . .Dq no .
Note that setting this option to Note that you need to set this option to
.Dq no .Dq yes
turns off if you want to use
.Cm RhostsAuthentication .Cm RhostsAuthentication
and and
.Cm RhostsRSAAuthentication .Cm RhostsRSAAuthentication
for older servers. with older servers.
.It Cm User .It Cm User
Specifies the user to log in as. Specifies the user to log in as.
This can be useful if you have a different user name on different machines. This can be useful if you have a different user name on different machines.
@ -1097,7 +1121,9 @@ the host where the shell runs, and n is an integer >= 1.
.Nm .Nm
uses this special value to forward X11 connections over the secure uses this special value to forward X11 connections over the secure
channel. channel.
The user should normally not set DISPLAY explicitly, as that The user should normally not set
.Ev DISPLAY
explicitly, as that
will render the X11 connection insecure (and will require the user to will render the X11 connection insecure (and will require the user to
manually copy any required authorization cookies). manually copy any required authorization cookies).
.It Ev HOME .It Ev HOME
@ -1211,7 +1237,7 @@ spaces).
This file is not highly sensitive, but the recommended This file is not highly sensitive, but the recommended
permissions are read/write for the user, and not accessible by others. permissions are read/write for the user, and not accessible by others.
.It Pa $HOME/.ssh/authorized_keys2 .It Pa $HOME/.ssh/authorized_keys2
Lists the public keys (DSA/RSA) that can be used for logging in as this user. Lists the public keys (RSA/DSA) that can be used for logging in as this user.
This file is not highly sensitive, but the recommended This file is not highly sensitive, but the recommended
permissions are read/write for the user, and not accessible by others. permissions are read/write for the user, and not accessible by others.
.It Pa /etc/ssh_known_hosts, /etc/ssh_known_hosts2 .It Pa /etc/ssh_known_hosts, /etc/ssh_known_hosts2
@ -1219,7 +1245,7 @@ Systemwide list of known host keys.
.Pa /etc/ssh_known_hosts .Pa /etc/ssh_known_hosts
contains RSA and contains RSA and
.Pa /etc/ssh_known_hosts2 .Pa /etc/ssh_known_hosts2
contains DSA or RSA keys for protocol version 2. contains RSA or DSA keys for protocol version 2.
These files should be prepared by the These files should be prepared by the
system administrator to contain the public host keys of all machines in the system administrator to contain the public host keys of all machines in the
organization. organization.

121
sshd.8
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@ -34,13 +34,13 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: sshd.8,v 1.119 2001/04/22 13:32:27 markus Exp $ .\" $OpenBSD: sshd.8,v 1.120 2001/04/22 23:58:36 markus Exp $
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSHD 8 .Dt SSHD 8
.Os .Os
.Sh NAME .Sh NAME
.Nm sshd .Nm sshd
.Nd OpenSSH ssh daemon .Nd OpenSSH SSH daemon
.Sh SYNOPSIS .Sh SYNOPSIS
.Nm sshd .Nm sshd
.Op Fl deiqD46 .Op Fl deiqD46
@ -134,8 +134,9 @@ Each host has a host-specific DSA key used to identify the host.
However, when the daemon starts, it does not generate a server key. However, when the daemon starts, it does not generate a server key.
Forward security is provided through a Diffie-Hellman key agreement. Forward security is provided through a Diffie-Hellman key agreement.
This key agreement results in a shared session key. This key agreement results in a shared session key.
.Pp
The rest of the session is encrypted using a symmetric cipher, currently The rest of the session is encrypted using a symmetric cipher, currently
Blowfish, 3DES, CAST128, Arcfour, 128 bit AES, or 256 bit AES. 128 bit AES, Blowfish, 3DES, CAST128, Arcfour, 192 bit AES, or 256 bit AES.
The client selects the encryption algorithm The client selects the encryption algorithm
to use from those offered by the server. to use from those offered by the server.
Additionally, session integrity is provided Additionally, session integrity is provided
@ -143,8 +144,9 @@ through a cryptographic message authentication code
(hmac-sha1 or hmac-md5). (hmac-sha1 or hmac-md5).
.Pp .Pp
Protocol version 2 provides a public key based Protocol version 2 provides a public key based
user authentication method (PubkeyAuthentication) user (PubkeyAuthentication) or
and conventional password authentication. client host (HostbasedAuthentication) authentication method,
conventional password authentication and challenge response based methods.
.Pp .Pp
.Ss Command execution and data forwarding .Ss Command execution and data forwarding
.Pp .Pp
@ -180,7 +182,8 @@ by executing itself with the name it was started as, ie.
The options are as follows: The options are as follows:
.Bl -tag -width Ds .Bl -tag -width Ds
.It Fl b Ar bits .It Fl b Ar bits
Specifies the number of bits in the server key (default 768). Specifies the number of bits in the ephemeral protocol version 1
server key (default 768).
.Pp .Pp
.It Fl d .It Fl d
Debug mode. Debug mode.
@ -188,8 +191,12 @@ The server sends verbose debug output to the system
log, and does not put itself in the background. log, and does not put itself in the background.
The server also will not fork and will only process one connection. The server also will not fork and will only process one connection.
This option is only intended for debugging for the server. This option is only intended for debugging for the server.
Multiple -d options increases the debugging level. Multiple -d options increase the debugging level.
Maximum is 3. Maximum is 3.
.It Fl e
When this option is specified,
.Nm
will send the output to the standard error instead of the system log.
.It Fl f Ar configuration_file .It Fl f Ar configuration_file
Specifies the name of the configuration file. Specifies the name of the configuration file.
The default is The default is
@ -210,7 +217,7 @@ This option must be given if
is not run as root (as the normal is not run as root (as the normal
host file is normally not readable by anyone but root). host file is normally not readable by anyone but root).
It is possible to have multiple host key files for It is possible to have multiple host key files for
the different protocol versions. the different protocol versions and host key algorithms.
.It Fl i .It Fl i
Specifies that Specifies that
.Nm .Nm
@ -225,8 +232,8 @@ However, with small key sizes (e.g., 512) using
from inetd may from inetd may
be feasible. be feasible.
.It Fl k Ar key_gen_time .It Fl k Ar key_gen_time
Specifies how often the server key is regenerated (default 3600 Specifies how often the ephemeral protocol version 1 server key is
seconds, or one hour). regenerated (default 3600 seconds, or one hour).
The motivation for regenerating the key fairly The motivation for regenerating the key fairly
often is that the key is not stored anywhere, and after about an hour, often is that the key is not stored anywhere, and after about an hour,
it becomes impossible to recover the key for decrypting intercepted it becomes impossible to recover the key for decrypting intercepted
@ -263,18 +270,6 @@ When this option is specified
will not detach and does not become a daemon. will not detach and does not become a daemon.
This allows easy monitoring of This allows easy monitoring of
.Nm sshd . .Nm sshd .
.It Fl e
When this option is specified,
.Nm
will send the output to the standard error instead of the system log.
.It Fl V Ar client_protocol_id
SSH-2 compatibility mode.
When this option is specified
.Nm
assumes the client has sent the supplied version string
and skips the
Protocol Version Identification Exchange.
This option is not intended to be called directly.
.It Fl 4 .It Fl 4
Forces Forces
.Nm .Nm
@ -426,6 +421,15 @@ or
.Dq no . .Dq no .
The default is The default is
.Dq no . .Dq no .
.It Cm HostbasedAuthentication
Specifies whether rhosts or /etc/hosts.equiv authentication together
with successful public key client host authentication is allowed
(hostbased authentication).
This option is similar to
.Cm RhostsRSAAuthentication
and applies to protocol version 2 only.
The default is
.Dq no .
.It Cm HostKey .It Cm HostKey
Specifies the file containing the private host keys (default Specifies the file containing the private host keys (default
.Pa /etc/ssh_host_key ) .Pa /etc/ssh_host_key )
@ -445,7 +449,12 @@ Specifies that
.Pa .rhosts .Pa .rhosts
and and
.Pa .shosts .Pa .shosts
files will not be used in authentication. files will not be used in
.Cm RhostsAuthentication ,
.Cm RhostsRSAAuthentication
or
.Cm HostbasedAuthentication .
.Pp
.Pa /etc/hosts.equiv .Pa /etc/hosts.equiv
and and
.Pa /etc/shosts.equiv .Pa /etc/shosts.equiv
@ -458,7 +467,9 @@ Specifies whether
should ignore the user's should ignore the user's
.Pa $HOME/.ssh/known_hosts .Pa $HOME/.ssh/known_hosts
during during
.Cm RhostsRSAAuthentication . .Cm RhostsRSAAuthentication
or
.Cm HostbasedAuthentication .
The default is The default is
.Dq no . .Dq no .
.It Cm KeepAlive .It Cm KeepAlive
@ -511,8 +522,8 @@ file on logout.
Default is Default is
.Dq yes . .Dq yes .
.It Cm KeyRegenerationInterval .It Cm KeyRegenerationInterval
The server key is automatically regenerated after this many seconds In protocol version 1, the ephemeral server key is automatically regenerated
(if it has been used). after this many seconds (if it has been used).
The purpose of regeneration is to prevent The purpose of regeneration is to prevent
decrypting captured sessions by later breaking into the machine and decrypting captured sessions by later breaking into the machine and
stealing the keys. stealing the keys.
@ -521,7 +532,7 @@ If the value is 0, the key is never regenerated.
The default is 3600 (seconds). The default is 3600 (seconds).
.It Cm ListenAddress .It Cm ListenAddress
Specifies the local addresses Specifies the local addresses
.Xr sshd 8 .Nm
should listen on. should listen on.
The following forms may be used: The following forms may be used:
.Pp .Pp
@ -547,7 +558,7 @@ The following forms may be used:
If If
.Ar port .Ar port
is not specified, is not specified,
.Xr sshd 8 .Nm
will listen on the address and all prior will listen on the address and all prior
.Cm Port .Cm Port
options specified. The default is to listen on all local options specified. The default is to listen on all local
@ -609,7 +620,6 @@ are refused if the number of unauthenticated connections reaches
Specifies whether password authentication is allowed. Specifies whether password authentication is allowed.
The default is The default is
.Dq yes . .Dq yes .
Note that this option applies to both protocol versions 1 and 2.
.It Cm PermitEmptyPasswords .It Cm PermitEmptyPasswords
When password authentication is allowed, it specifies whether the When password authentication is allowed, it specifies whether the
server allows login to accounts with empty password strings. server allows login to accounts with empty password strings.
@ -656,6 +666,8 @@ Specifies the port number that
listens on. listens on.
The default is 22. The default is 22.
Multiple options of this type are permitted. Multiple options of this type are permitted.
See also
.Cm ListenAddress .
.It Cm PrintLastLog .It Cm PrintLastLog
Specifies whether Specifies whether
.Nm .Nm
@ -707,18 +719,20 @@ instead, because it performs RSA-based host authentication in addition
to normal rhosts or /etc/hosts.equiv authentication. to normal rhosts or /etc/hosts.equiv authentication.
The default is The default is
.Dq no . .Dq no .
This option applies to protocol version 1 only.
.It Cm RhostsRSAAuthentication .It Cm RhostsRSAAuthentication
Specifies whether rhosts or /etc/hosts.equiv authentication together Specifies whether rhosts or /etc/hosts.equiv authentication together
with successful RSA host authentication is allowed. with successful RSA host authentication is allowed.
The default is The default is
.Dq no . .Dq no .
This option applies to protocol version 1 only.
.It Cm RSAAuthentication .It Cm RSAAuthentication
Specifies whether pure RSA authentication is allowed. Specifies whether pure RSA authentication is allowed.
The default is The default is
.Dq yes . .Dq yes .
Note that this option applies to protocol version 1 only. This option applies to protocol version 1 only.
.It Cm ServerKeyBits .It Cm ServerKeyBits
Defines the number of bits in the server key. Defines the number of bits in the ephemeral protocol version 1 server key.
The minimum value is 512, and the default is 768. The minimum value is 512, and the default is 768.
.It Cm StrictModes .It Cm StrictModes
Specifies whether Specifies whether
@ -825,12 +839,12 @@ Runs user's shell or command.
The The
.Pa $HOME/.ssh/authorized_keys .Pa $HOME/.ssh/authorized_keys
file lists the RSA keys that are file lists the RSA keys that are
permitted for RSA authentication in SSH protocols 1.3 and 1.5 permitted for RSA authentication in protocol version 1
Similarly, the Similarly, the
.Pa $HOME/.ssh/authorized_keys2 .Pa $HOME/.ssh/authorized_keys2
file lists the DSA and RSA keys that are file lists the DSA and RSA keys that are
permitted for public key authentication (PubkeyAuthentication) permitted for public key authentication (PubkeyAuthentication)
in SSH protocol 2.0. in protocol version 2.
.Pp .Pp
Each line of the file contains one Each line of the file contains one
key (empty lines and lines starting with a key (empty lines and lines starting with a
@ -994,7 +1008,10 @@ or by taking
.Pa /etc/ssh_host_key.pub .Pa /etc/ssh_host_key.pub
and adding the host names at the front. and adding the host names at the front.
.Ss Examples .Ss Examples
closenet,closenet.hut.fi,.\|.\|.\|,130.233.208.41 1024 37 159.\|.\|.93 closenet.hut.fi .Bd -literal
closenet,.\|.\|.\|,130.233.208.41 1024 37 159.\|.\|.93 closenet.hut.fi
cvs.openbsd.org,199.185.137.3 ssh-rsa AAAA1234.....=
.Ed
.Sh FILES .Sh FILES
.Bl -tag -width Ds .Bl -tag -width Ds
.It Pa /etc/sshd_config .It Pa /etc/sshd_config
@ -1003,16 +1020,14 @@ Contains configuration data for
This file should be writable by root only, but it is recommended This file should be writable by root only, but it is recommended
(though not necessary) that it be world-readable. (though not necessary) that it be world-readable.
.It Pa /etc/ssh_host_key, /etc/ssh_host_dsa_key, /etc/ssh_host_rsa_key .It Pa /etc/ssh_host_key, /etc/ssh_host_dsa_key, /etc/ssh_host_rsa_key
These three files contain the private parts of the These three files contain the private parts of the host keys.
(SSH1, SSH2 DSA, and SSH2 RSA) host keys.
These files should only be owned by root, readable only by root, and not These files should only be owned by root, readable only by root, and not
accessible to others. accessible to others.
Note that Note that
.Nm .Nm
does not start if this file is group/world-accessible. does not start if this file is group/world-accessible.
.It Pa /etc/ssh_host_key.pub, /etc/ssh_host_dsa_key.pub, /etc/ssh_host_rsa_key.pub .It Pa /etc/ssh_host_key.pub, /etc/ssh_host_dsa_key.pub, /etc/ssh_host_rsa_key.pub
These three files contain the public parts of the These three files contain the public parts of the host keys.
(SSH1, SSH2 DSA, and SSH2 RSA) host keys.
These files should be world-readable but writable only by These files should be world-readable but writable only by
root. root.
Their contents should match the respective private parts. Their contents should match the respective private parts.
@ -1042,7 +1057,7 @@ Users will place the contents of their
files into this file, as described in files into this file, as described in
.Xr ssh-keygen 1 . .Xr ssh-keygen 1 .
.It Pa $HOME/.ssh/authorized_keys2 .It Pa $HOME/.ssh/authorized_keys2
Lists the DSA keys that can be used to log into the user's account. Lists the public keys (RSA or DSA) that can be used to log into the user's account.
This file must be readable by root (which may on some machines imply This file must be readable by root (which may on some machines imply
it being world-readable if the user's home directory resides on an NFS it being world-readable if the user's home directory resides on an NFS
volume). volume).
@ -1065,6 +1080,17 @@ These files should be writable only by root/the owner.
should be world-readable, and should be world-readable, and
.Pa $HOME/.ssh/known_hosts .Pa $HOME/.ssh/known_hosts
can but need not be world-readable. can but need not be world-readable.
.It Pa "/etc/ssh_known_hosts2" and "$HOME/.ssh/known_hosts2"
These files are consulted when using protocol version 2 hostbased
authentication to check the public key of the host.
The key must be listed in one of these files to be accepted.
The client uses the same files
to verify that it is connecting to the correct remote host.
These files should be writable only by root/the owner.
.Pa /etc/ssh_known_hosts2
should be world-readable, and
.Pa $HOME/.ssh/known_hosts2
can but need not be world-readable.
.It Pa /etc/nologin .It Pa /etc/nologin
If this file exists, If this file exists,
.Nm .Nm
@ -1162,8 +1188,12 @@ which may be needed before the user's home directory becomes
accessible; AFS is a particular example of such an environment. accessible; AFS is a particular example of such an environment.
.Pp .Pp
This file will probably contain some initialization code followed by This file will probably contain some initialization code followed by
something similar to: "if read proto cookie; then echo add $DISPLAY something similar to:
$proto $cookie | xauth -q -; fi". .Bd -literal
if read proto cookie; then
echo add $DISPLAY $proto $cookie | xauth -q -
fi
.Ed
.Pp .Pp
If this file does not exist, If this file does not exist,
.Pa /etc/sshrc .Pa /etc/sshrc
@ -1209,3 +1239,12 @@ protocol versions 1.5 and 2.0.
.%D January 2001 .%D January 2001
.%O work in progress material .%O work in progress material
.Re .Re
.Rs
.%A M. Friedl
.%A N. Provos
.%A W. A. Simpson
.%T "Diffie-Hellman Group Exchange for the SSH Transport Layer Protocol"
.%N draft-ietf-secsh-dh-group-exchange-00.txt
.%D January 2001
.%O work in progress material
.Re