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authorJason McIntyre <jmc@cvs.openbsd.org>2006-02-01 09:06:51 +0000
committerJason McIntyre <jmc@cvs.openbsd.org>2006-02-01 09:06:51 +0000
commit99b3f6be7deb1f6217d9d3db33abe5c6e3a634ed (patch)
tree256e824647251bcddebb845517ca9e952db6a658
parent74b6d652e7ced580c94cfacacf1101924f34c27b (diff)
- merge sections on protocols 1 and 2 into a single section
- remove configuration file section ok markus
-rw-r--r--usr.bin/ssh/sshd.881
1 files changed, 35 insertions, 46 deletions
diff --git a/usr.bin/ssh/sshd.8 b/usr.bin/ssh/sshd.8
index e94b95fbfd7..7cd97aa1743 100644
--- a/usr.bin/ssh/sshd.8
+++ b/usr.bin/ssh/sshd.8
@@ -34,7 +34,7 @@
.\" (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: sshd.8,v 1.213 2006/01/25 09:07:22 jmc Exp $
+.\" $OpenBSD: sshd.8,v 1.214 2006/02/01 09:06:50 jmc Exp $
.Dd September 25, 1999
.Dt SSHD 8
.Os
@@ -227,20 +227,26 @@ USER@HOST pattern in
or
.Cm DenyUsers .
.El
-.Pp
-This implementation of
-.Nm
-supports both SSH protocol version 1 and 2 simultaneously.
-.Nm
-works as follows:
-.Sh SSH PROTOCOL VERSION 1
-Each host has a host-specific RSA key
-(normally 2048 bits) used to identify the host.
-Additionally, when
-the daemon starts, it generates a server RSA key (normally 768 bits).
+.Sh AUTHENTICATION
+The OpenSSH SSH daemon supports SSH protocols 1 and 2.
+Both protocols are supported by default,
+though this can be changed via the
+.Cm Protocol
+option in
+.Xr sshd_config 5 .
+Protocol 2 supports both RSA and DSA keys;
+protocol 1 only supports RSA keys.
+For both protocols,
+each host has a host-specific key,
+normally 2048 bits,
+used to identify the host.
+.Pp
+Forward security for protocol 1 is provided through
+an additional server key,
+normally 768 bits,
+generated when the server starts.
This key is normally regenerated every hour if it has been used, and
is never stored on disk.
-.Pp
Whenever a client connects, the daemon responds with its public
host and server keys.
The client compares the
@@ -258,12 +264,23 @@ being used by default.
The client selects the encryption algorithm
to use from those offered by the server.
.Pp
-Next, the server and the client enter an authentication dialog.
+For protocol 2,
+forward security is provided through a Diffie-Hellman key agreement.
+This key agreement results in a shared session key.
+The rest of the session is encrypted using a symmetric cipher, currently
+128-bit AES, Blowfish, 3DES, CAST128, Arcfour, 192-bit AES, or 256-bit AES.
+The client selects the encryption algorithm
+to use from those offered by the server.
+Additionally, session integrity is provided
+through a cryptographic message authentication code
+(hmac-sha1 or hmac-md5).
+.Pp
+Finally, the server and the client enter an authentication dialog.
The client tries to authenticate itself using
-.Em rhosts
-authentication combined with RSA host
-authentication, RSA challenge-response authentication, or password
-based authentication.
+host-based authentication,
+public key authentication,
+challenge-response authentication,
+or password authentication.
.Pp
System security is not improved unless
.Nm rshd ,
@@ -275,25 +292,6 @@ are disabled (thus completely disabling
and
.Xr rsh
into the machine).
-.Sh SSH PROTOCOL VERSION 2
-Version 2 works similarly:
-Each host has a host-specific key (RSA or DSA) used to identify the host.
-However, when the daemon starts, it does not generate a server key.
-Forward security is provided through a Diffie-Hellman key agreement.
-This key agreement results in a shared session key.
-.Pp
-The rest of the session is encrypted using a symmetric cipher, currently
-128-bit AES, Blowfish, 3DES, CAST128, Arcfour, 192-bit AES, or 256-bit AES.
-The client selects the encryption algorithm
-to use from those offered by the server.
-Additionally, session integrity is provided
-through a cryptographic message authentication code
-(hmac-sha1 or hmac-md5).
-.Pp
-Protocol version 2 provides a public key based
-user (PubkeyAuthentication) or
-client host (HostbasedAuthentication) authentication method,
-conventional password authentication and challenge response based methods.
.Sh COMMAND EXECUTION AND DATA FORWARDING
If the client successfully authenticates itself, a dialog for
preparing the session is entered.
@@ -311,15 +309,6 @@ command on the server side, and the user terminal in the client side.
When the user program terminates and all forwarded X11 and other
connections have been closed, the server sends command exit status to
the client, and both sides exit.
-.Sh CONFIGURATION FILE
-.Nm
-reads configuration data from
-.Pa /etc/ssh/sshd_config
-(or the file specified with
-.Fl f
-on the command line).
-The file format and configuration options are described in
-.Xr sshd_config 5 .
.Sh LOGIN PROCESS
When a user successfully logs in,
.Nm