.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: ssh.1,v 1.205 2005/03/07 23:41:54 jmc Exp $
+.\" $OpenBSD: ssh.1,v 1.209 2005/07/06 09:33:05 dtucker Exp $
.Dd September 25, 1999
.Dt SSH 1
.Os
.Pa /etc/shosts.equiv
on the remote machine, and the user names are
the same on both sides, or if the files
-.Pa $HOME/.rhosts
+.Pa ~/.rhosts
or
-.Pa $HOME/.shosts
+.Pa ~/.shosts
exist in the user's home directory on the
remote machine and contain a line containing the name of the client
machine and the name of the user on that machine, the user is
host key (see
.Pa /etc/ssh/ssh_known_hosts
and
-.Pa $HOME/.ssh/known_hosts
+.Pa ~/.ssh/known_hosts
in the
.Sx FILES
section), only then is login permitted.
spoofing, DNS spoofing and routing spoofing.
[Note to the administrator:
.Pa /etc/hosts.equiv ,
-.Pa $HOME/.rhosts ,
+.Pa ~/.rhosts ,
and the rlogin/rsh protocol in general, are inherently insecure and should be
disabled if security is desired.]
.Pp
The server knows the public key, and only the user knows the private key.
.Pp
The file
-.Pa $HOME/.ssh/authorized_keys
+.Pa ~/.ssh/authorized_keys
lists the public keys that are permitted for logging in.
When the user logs in, the
.Nm
The user creates his/her RSA key pair by running
.Xr ssh-keygen 1 .
This stores the private key in
-.Pa $HOME/.ssh/identity
+.Pa ~/.ssh/identity
and stores the public key in
-.Pa $HOME/.ssh/identity.pub
+.Pa ~/.ssh/identity.pub
in the user's home directory.
The user should then copy the
.Pa identity.pub
to
-.Pa $HOME/.ssh/authorized_keys
+.Pa ~/.ssh/authorized_keys
in his/her home directory on the remote machine (the
.Pa authorized_keys
file corresponds to the conventional
-.Pa $HOME/.rhosts
+.Pa ~/.rhosts
file, and has one key
per line, though the lines can be very long).
After this, the user can log in without giving the password.
The public key method is similar to RSA authentication described
in the previous section and allows the RSA or DSA algorithm to be used:
The client uses his private key,
-.Pa $HOME/.ssh/id_dsa
+.Pa ~/.ssh/id_dsa
or
-.Pa $HOME/.ssh/id_rsa ,
+.Pa ~/.ssh/id_rsa ,
to sign the session identifier and sends the result to the server.
The server checks whether the matching public key is listed in
-.Pa $HOME/.ssh/authorized_keys
+.Pa ~/.ssh/authorized_keys
and grants access if both the key is found and the signature is correct.
The session identifier is derived from a shared Diffie-Hellman value
and is only known to the client and the server.
automatically maintains and checks a database containing
identifications for all hosts it has ever been used with.
Host keys are stored in
-.Pa $HOME/.ssh/known_hosts
+.Pa ~/.ssh/known_hosts
in the user's home directory.
Additionally, the file
.Pa /etc/ssh/ssh_known_hosts
.It Fl a
Disables forwarding of the authentication agent connection.
.It Fl b Ar bind_address
-Specify the interface to transmit from on machines with multiple
-interfaces or aliased addresses.
+Use
+.Ar bind_address
+on the local machine as the source address
+of the connection.
+Only useful on systems with more than one address.
.It Fl C
Requests compression of all data (including stdin, stdout, stderr, and
data for forwarded X11 and TCP/IP connections).
.Dq aes128-ctr ,
.Dq aes192-ctr ,
.Dq aes256-ctr ,
+.Dq arcfour128 ,
+.Dq arcfour256 ,
.Dq arcfour ,
.Dq blowfish-cbc ,
and
.Dq cast128-cbc .
The default is
.Bd -literal
- ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
- aes192-cbc,aes256-cbc''
+ ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,
+ arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr,
+ aes192-ctr,aes256-ctr''
.Ed
.It Fl D Ar port
Specifies a local
.Pq Pa /etc/ssh/ssh_config
will be ignored.
The default for the per-user configuration file is
-.Pa $HOME/.ssh/config .
+.Pa ~/.ssh/config .
.It Fl f
Requests
.Nm
Selects a file from which the identity (private key) for
RSA or DSA authentication is read.
The default is
-.Pa $HOME/.ssh/identity
+.Pa ~/.ssh/identity
for protocol version 1, and
-.Pa $HOME/.ssh/id_rsa
+.Pa ~/.ssh/id_rsa
and
-.Pa $HOME/.ssh/id_dsa
+.Pa ~/.ssh/id_dsa
for protocol version 2.
Identity files may also be specified on
a per-host basis in the configuration file.
Additionally,
.Nm
reads
-.Pa $HOME/.ssh/environment ,
+.Pa ~/.ssh/environment ,
and adds lines of the format
.Dq VARNAME=value
to the environment if the file exists and if users are allowed to
.Xr sshd_config 5 .
.Sh FILES
.Bl -tag -width Ds
-.It Pa $HOME/.ssh/known_hosts
+.It Pa ~/.ssh/known_hosts
Records host keys for all hosts the user has logged into that are not
in
.Pa /etc/ssh/ssh_known_hosts .
See
.Xr sshd 8 .
-.It Pa $HOME/.ssh/identity, $HOME/.ssh/id_dsa, $HOME/.ssh/id_rsa
+.It Pa ~/.ssh/identity, ~/.ssh/id_dsa, ~/.ssh/id_rsa
Contains the authentication identity of the user.
They are for protocol 1 RSA, protocol 2 DSA, and protocol 2 RSA, respectively.
These files
It is possible to specify a passphrase when
generating the key; the passphrase will be used to encrypt the
sensitive part of this file using 3DES.
-.It Pa $HOME/.ssh/identity.pub, $HOME/.ssh/id_dsa.pub, $HOME/.ssh/id_rsa.pub
+.It Pa ~/.ssh/identity.pub, ~/.ssh/id_dsa.pub, ~/.ssh/id_rsa.pub
Contains the public key for authentication (public part of the
identity file in human-readable form).
The contents of the
-.Pa $HOME/.ssh/identity.pub
+.Pa ~/.ssh/identity.pub
file should be added to the file
-.Pa $HOME/.ssh/authorized_keys
+.Pa ~/.ssh/authorized_keys
on all machines
where the user wishes to log in using protocol version 1 RSA authentication.
The contents of the
-.Pa $HOME/.ssh/id_dsa.pub
+.Pa ~/.ssh/id_dsa.pub
and
-.Pa $HOME/.ssh/id_rsa.pub
+.Pa ~/.ssh/id_rsa.pub
file should be added to
-.Pa $HOME/.ssh/authorized_keys
+.Pa ~/.ssh/authorized_keys
on all machines
where the user wishes to log in using protocol version 2 DSA/RSA authentication.
These files are not
These files are
never used automatically and are not necessary; they are only provided for
the convenience of the user.
-.It Pa $HOME/.ssh/config
+.It Pa ~/.ssh/config
This is the per-user configuration file.
The file format and configuration options are described in
.Xr ssh_config 5 .
Because of the potential for abuse, this file must have strict permissions:
read/write for the user, and not accessible by others.
-.It Pa $HOME/.ssh/authorized_keys
+.It Pa ~/.ssh/authorized_keys
Lists the public keys (RSA/DSA) that can be used for logging in as this user.
The format of this file is described in the
.Xr sshd 8
By default
.Nm
is not setuid root.
-.It Pa $HOME/.rhosts
+.It Pa ~/.rhosts
This file is used in
.Cm RhostsRSAAuthentication
and
If the server machine does not have the client's host key in
.Pa /etc/ssh/ssh_known_hosts ,
it can be stored in
-.Pa $HOME/.ssh/known_hosts .
+.Pa ~/.ssh/known_hosts .
The easiest way to do this is to
connect back to the client from the server machine using ssh; this
will automatically add the host key to
-.Pa $HOME/.ssh/known_hosts .
-.It Pa $HOME/.shosts
+.Pa ~/.ssh/known_hosts .
+.It Pa ~/.shosts
This file is used exactly the same way as
.Pa .rhosts .
The purpose for
See the
.Xr sshd 8
manual page for more information.
-.It Pa $HOME/.ssh/rc
+.It Pa ~/.ssh/rc
Commands in this file are executed by
.Nm
when the user logs in just before the user's shell (or command) is
See the
.Xr sshd 8
manual page for more information.
-.It Pa $HOME/.ssh/environment
+.It Pa ~/.ssh/environment
Contains additional definitions for environment variables, see section
.Sx ENVIRONMENT
above.
andersk / gssapi-openssh.git / blobdiff