===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/sshd.8,v
retrieving revision 1.51
retrieving revision 1.51.2.5
diff -u -r1.51 -r1.51.2.5
--- src/usr.bin/ssh/sshd.8	2000/05/08 17:42:31	1.51
+++ src/usr.bin/ssh/sshd.8	2001/03/21 18:53:16	1.51.2.5
@@ -1,35 +1,60 @@
 .\"  -*- nroff -*-
 .\"
-.\" sshd.8.in
-.\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
-.\"
 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 .\"                    All rights reserved
 .\"
-.\" Created: Sat Apr 22 21:55:14 1995 ylo
+.\" As far as I am concerned, the code I have written for this software
+.\" can be used freely for any purpose.  Any derived versions of this
+.\" software must be clearly marked as such, and if the derived work is
+.\" incompatible with the protocol description in the RFC file, it must be
+.\" called by a name other than "ssh" or "Secure Shell".
 .\"
-.\" $Id: sshd.8,v 1.51 2000/05/08 17:42:31 hugh Exp $
+.\" Copyright (c) 1999,2000 Markus Friedl.  All rights reserved.
+.\" Copyright (c) 1999 Aaron Campbell.  All rights reserved.
+.\" Copyright (c) 1999 Theo de Raadt.  All rights reserved.
 .\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (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 1.51.2.5 2001/03/21 18:53:16 jason Exp $
 .Dd September 25, 1999
 .Dt SSHD 8
 .Os
 .Sh NAME
 .Nm sshd
-.Nd secure shell daemon
+.Nd OpenSSH ssh daemon
 .Sh SYNOPSIS
 .Nm sshd
-.Op Fl diqQ46
+.Op Fl diqD46
 .Op Fl b Ar bits
 .Op Fl f Ar config_file
 .Op Fl g Ar login_grace_time
 .Op Fl h Ar host_key_file
 .Op Fl k Ar key_gen_time
 .Op Fl p Ar port
+.Op Fl u Ar len
 .Op Fl V Ar client_protocol_id
 .Sh DESCRIPTION
 .Nm
-(Secure Shell Daemon) is the daemon program for
+(SSH Daemon) is the daemon program for
 .Xr ssh 1 .
 Together these programs replace rlogin and rsh, and
 provide secure encrypted communications between two untrusted hosts
@@ -104,14 +129,13 @@
 .Pp
 .Ss SSH protocol version 2
 .Pp
-Version 2 works similar:
+Version 2 works similarly:
 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.
 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
-Blowfish, 3DES or CAST128 in CBC mode or Arcfour.
+The rest of the session is encrypted using a symmetric cipher, currently
+Blowfish, 3DES, CAST128, Arcfour, 128 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
@@ -119,7 +143,7 @@
 (hmac-sha1 or hmac-md5).
 .Pp
 Protocol version 2 provides a public key based
-user authentication method (DSAAuthentication)
+user authentication method (PubkeyAuthentication)
 and conventional password authentication.
 .Pp
 .Ss Command execution and data forwarding
@@ -149,7 +173,9 @@
 .Pp
 .Nm
 rereads its configuration file when it receives a hangup signal,
-.Dv SIGHUP .
+.Dv SIGHUP ,
+by executing itself with the name it was started as, ie.
+.Pa /usr/sbin/sshd .
 .Pp
 The options are as follows:
 .Bl -tag -width Ds
@@ -162,6 +188,8 @@
 log, and does not put itself in the background.
 The server also will not fork and will only process one connection.
 This option is only intended for debugging for the server.
+Multiple -d options increases the debugging level.
+Maximum is 3.
 .It Fl f Ar configuration_file
 Specifies the name of the configuration file.
 The default is
@@ -170,17 +198,19 @@
 refuses to start if there is no configuration file.
 .It Fl g Ar login_grace_time
 Gives the grace time for clients to authenticate themselves (default
-300 seconds).
+600 seconds).
 If the client fails to authenticate the user within
 this many seconds, the server disconnects and exits.
 A value of zero indicates no limit.
 .It Fl h Ar host_key_file
-Specifies the file from which the RSA host key is read (default
+Specifies the file from which the host key is read (default
 .Pa /etc/ssh_host_key ) .
 This option must be given if
 .Nm
 is not run as root (as the normal
 host file is normally not readable by anyone but root).
+It is possible to have multiple host key files for
+the different protocol versions.
 .It Fl i
 Specifies that
 .Nm
@@ -211,15 +241,36 @@
 Nothing is sent to the system log.
 Normally the beginning,
 authentication, and termination of each connection is logged.
-.It Fl Q
-Do not print an error message if RSA support is missing.
+.It Fl u Ar len
+This option is used to specify the size of the field
+in the
+.Li utmp
+structure that holds the remote host name.
+If the resolved host name is longer than
+.Ar len ,
+the dotted decimal value will be used instead.
+This allows hosts with very long host names that
+overflow this field to still be uniquely identified.
+Specifying
+.Fl u0
+indicates that only dotted decimal addresses
+should be put into the
+.Pa utmp
+file.
+.It Fl D
+When this option is specified
+.Nm
+will not detach and does not become a daemon.
+This allows easy monitoring of
+.Nm sshd .
 .It Fl V Ar client_protocol_id
-SSH2 compatibility mode.
+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
 Forces
 .Nm
@@ -248,20 +299,28 @@
 Default is
 .Dq yes .
 .It Cm AllowGroups
-This keyword can be followed by a number of group names, separated
+This keyword can be followed by a list of group names, separated
 by spaces.
 If specified, login is allowed only for users whose primary
-group matches one of the patterns.
+group or supplementary group list matches one of the patterns.
 .Ql \&*
 and
 .Ql ?
 can be used as
 wildcards in the patterns.
-Only group names are valid, a numerical group ID isn't recognized.
-By default login is allowed regardless of the primary group.
+Only group names are valid; a numerical group ID isn't recognized.
+By default login is allowed regardless of the group list.
 .Pp
+.It Cm AllowTcpForwarding
+Specifies whether TCP forwarding is permitted.
+The default is
+.Dq yes .
+Note that disabling TCP forwarding does not improve security unless
+users are also denied shell access, as they can always install their
+own forwarders.
+.Pp
 .It Cm AllowUsers
-This keyword can be followed by a number of user names, separated
+This keyword can be followed by a list of user names, separated
 by spaces.
 If specified, login is allowed only for users names that
 match one of the patterns.
@@ -270,14 +329,30 @@
 .Ql ?
 can be used as
 wildcards in the patterns.
-Only user names are valid, a numerical user ID isn't recognized.
+Only user names are valid; a numerical user ID isn't recognized.
 By default login is allowed regardless of the user name.
 .Pp
+.It Cm Banner
+In some jurisdictions, sending a warning message before authentication
+may be relevant for getting legal protection.
+The contents of the specified file are sent to the remote user before
+authentication is allowed.
+This option is only available for protocol version 2.
+.Pp
+.It Cm ChallengeResponseAuthentication
+Specifies whether
+challenge response
+authentication is allowed.
+Currently there is only support for
+.Xr skey 1
+authentication.
+The default is
+.Dq yes .
 .It Cm Ciphers
 Specifies the ciphers allowed for protocol version 2.
 Multiple ciphers must be comma-separated.
 The default is
-.Dq 3des-cbc,blowfish-cbc,arcfour,cast128-cbc .
+.Dq aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour.
 .It Cm CheckMail
 Specifies whether
 .Nm
@@ -287,15 +362,15 @@
 .It Cm DenyGroups
 This keyword can be followed by a number of group names, separated
 by spaces.
-Users whose primary group matches one of the patterns
-aren't allowed to log in.
+Users whose primary group or supplementary group list matches
+one of the patterns aren't allowed to log in.
 .Ql \&*
 and
 .Ql ?
 can be used as
 wildcards in the patterns.
-Only group names are valid, a numerical group ID isn't recognized.
-By default login is allowed regardless of the primary group.
+Only group names are valid; a numerical group ID isn't recognized.
+By default login is allowed regardless of the group list.
 .Pp
 .It Cm DenyUsers
 This keyword can be followed by a number of user names, separated
@@ -305,13 +380,8 @@
 and
 .Ql ?
 can be used as wildcards in the patterns.
-Only user names are valid, a numerical user ID isn't recognized.
+Only user names are valid; a numerical user ID isn't recognized.
 By default login is allowed regardless of the user name.
-.It Cm DSAAuthentication
-Specifies whether DSA authentication is allowed.
-The default is
-.Dq yes .
-Note that this option applies to protocol version 2 only.
 .It Cm GatewayPorts
 Specifies whether remote hosts are allowed to connect to ports
 forwarded for the client.
@@ -321,20 +391,20 @@
 .Dq no .
 The default is
 .Dq no .
-.It Cm HostDsaKey
-Specifies the file containing the private DSA host key (default
-.Pa /etc/ssh_host_dsa_key )
-used by SSH protocol 2.0.
-Note that
-.Nm
-disables protocol 2.0 if this file is group/world-accessible.
 .It Cm HostKey
-Specifies the file containing the private RSA host key (default
+Specifies the file containing the private host keys (default
 .Pa /etc/ssh_host_key )
-used by SSH protocols 1.3 and 1.5.
+used by SSH protocol versions 1 and 2.
 Note that
 .Nm
-disables protocols 1.3 and 1.5 if this file is group/world-accessible.
+will refuse to use a file if it is group/world-accessible.
+It is possible to have multiple host key files.
+.Dq rsa1
+keys are used for version 1 and
+.Dq dsa
+or
+.Dq rsa
+are used for version 2 of the SSH protocol.
 .It Cm IgnoreRhosts
 Specifies that
 .Pa .rhosts
@@ -384,14 +454,15 @@
 .Cm PasswordAuthentication
 is yes, the password provided by the user will be validated through
 the Kerberos KDC.
+To use this option, the server needs a
+Kerberos servtab which allows the verification of the KDC's identity.
 Default is
 .Dq yes .
 .It Cm KerberosOrLocalPasswd
 If set then if password authentication through Kerberos fails then
 the password will be validated via any additional local mechanism
 such as
-.Pa /etc/passwd
-or SecurID.
+.Pa /etc/passwd .
 Default is
 .Dq yes .
 .It Cm KerberosTgtPassing
@@ -435,36 +506,81 @@
 The default is INFO.
 Logging with level DEBUG violates the privacy of users
 and is not recommended.
+.It Cm MACs
+Specifies the available MAC (message authentication code) algorithms.
+The MAC algorithm is used in protocol version 2
+for data integrity protection.
+Multiple algorithms must be comma-separated.
+The default is
+.Pp
+.Bd -literal
+  ``hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,
+    hmac-sha1-96,hmac-md5-96''
+.Ed
+.It Cm MaxStartups
+Specifies the maximum number of concurrent unauthenticated connections to the
+.Nm
+daemon.
+Additional connections will be dropped until authentication succeeds or the
+.Cm LoginGraceTime
+expires for a connection.
+The default is 10.
+.Pp
+Alternatively, random early drop can be enabled by specifying
+the three colon separated values
+.Dq start:rate:full
+(e.g., "10:30:60").
+.Nm
+will refuse connection attempts with a probability of
+.Dq rate/100
+(30%)
+if there are currently
+.Dq start
+(10)
+unauthenticated connections.
+The probability increases linearly and all connection attempts
+are refused if the number of unauthenticated connections reaches
+.Dq full
+(60).
 .It Cm PasswordAuthentication
 Specifies whether password authentication is allowed.
 The default is
 .Dq yes .
-Note that this option applies to both protocol version 1 and 2.
+Note that this option applies to both protocol versions 1 and 2.
 .It Cm PermitEmptyPasswords
 When password authentication is allowed, it specifies whether the
 server allows login to accounts with empty password strings.
 The default is
 .Dq no .
 .It Cm PermitRootLogin
-Specifies whether the root can log in using
+Specifies whether root can login using
 .Xr ssh 1 .
 The argument must be
 .Dq yes ,
-.Dq without-password
+.Dq without-password ,
+.Dq forced-commands-only
 or
 .Dq no .
 The default is
 .Dq yes .
-If this options is set to
+.Pp
+If this option is set to
 .Dq without-password
-only password authentication is disabled for root.
+password authentication is disabled for root.
 .Pp
-Root login with RSA authentication when the
+If this option is set to
+.Dq forced-commands-only
+root login with public key authentication will be allowed,
+but only if the
 .Ar command
-option has been
-specified will be allowed regardless of the value of this setting
+option has been specified
 (which may be useful for taking remote backups even if root login is
-normally not allowed).
+normally not allowed). All other authentication methods are disabled
+for root.
+.Pp
+If this option is set to
+.Dq no
+root is not allowed to login.
 .It Cm PidFile
 Specifies the file that contains the process identifier of the
 .Nm
@@ -499,9 +615,19 @@
 Multiple versions must be comma-separated.
 The default is
 .Dq 1 .
-.It Cm RandomSeed
-Obsolete.
-Random number generation uses other techniques.
+.It Cm PubkeyAuthentication
+Specifies whether public key authentication is allowed.
+The default is
+.Dq yes .
+Note that this option applies to protocol version 2 only.
+.It Cm ReverseMappingCheck
+Specifies whether
+.Nm
+should try to verify the remote host name and check that
+the resolved host name for the remote IP address maps back to the
+very same IP address.
+The default is
+.Dq no .
 .It Cm RhostsAuthentication
 Specifies whether authentication using rhosts or /etc/hosts.equiv
 files is sufficient.
@@ -525,15 +651,6 @@
 .It Cm ServerKeyBits
 Defines the number of bits in the server key.
 The minimum value is 512, and the default is 768.
-.It Cm SkeyAuthentication
-Specifies whether
-.Xr skey 1
-authentication is allowed.
-The default is
-.Dq yes .
-Note that s/key authentication is enabled only if
-.Cm PasswordAuthentication
-is allowed, too.
 .It Cm StrictModes
 Specifies whether
 .Nm
@@ -543,6 +660,17 @@
 directory or files world-writable.
 The default is
 .Dq yes .
+.It Cm Subsystem
+Configures an external subsystem (e.g., file transfer daemon).
+Arguments should be a subsystem name and a command to execute upon subsystem
+request.
+The command
+.Xr sftp-server 8
+implements the
+.Dq sftp
+file transfer subsystem.
+By default no subsystems are defined.
+Note that this option applies to protocol version 2 only.
 .It Cm SyslogFacility
 Gives the facility code that is used when logging messages from
 .Nm sshd .
@@ -552,7 +680,10 @@
 .It Cm UseLogin
 Specifies whether
 .Xr login 1
-is used.
+is used for interactive login sessions.
+Note that
+.Xr login 1
+is never used for remote command execution.
 The default is
 .Dq no .
 .It Cm X11DisplayOffset
@@ -569,6 +700,12 @@
 .Dq no .
 Note that disabling X11 forwarding does not improve security in any
 way, as users can always install their own forwarders.
+.It Cm XAuthLocation
+Specifies the location of the
+.Xr xauth 1
+program.
+The default is
+.Pa /usr/X11R6/bin/xauth .
 .El
 .Sh LOGIN PROCESS
 When a user successfully logs in,
@@ -622,29 +759,40 @@
 permitted for RSA authentication in SSH protocols 1.3 and 1.5
 Similarly, the
 .Pa $HOME/.ssh/authorized_keys2
-file lists the DSA keys that are
-permitted for DSA authentication in SSH protocol 2.0.
+file lists the DSA and RSA keys that are
+permitted for public key authentication (PubkeyAuthentication)
+in SSH protocol 2.0.
+.Pp
 Each line of the file contains one
 key (empty lines and lines starting with a
 .Ql #
 are ignored as
 comments).
-Each line consists of the following fields, separated by
+Each RSA public key consists of the following fields, separated by
 spaces: options, bits, exponent, modulus, comment.
-The options field
-is optional; its presence is determined by whether the line starts
+Each protocol version 2 public key consists of:
+options, keytype, base64 encoded key, comment.
+The options fields
+are optional; its presence is determined by whether the line starts
 with a number or not (the option field never starts with a number).
-The bits, exponent, modulus and comment fields give the RSA key; the
+The bits, exponent, modulus and comment fields give the RSA key for
+protocol version 1; the
 comment field is not used for anything (but may be convenient for the
 user to identify the key).
+For protocol version 2 the keytype is
+.Dq ssh-dss
+or
+.Dq ssh-rsa .
 .Pp
 Note that lines in this file are usually several hundred bytes long
 (because of the size of the RSA key modulus).
 You don't want to type them in; instead, copy the
 .Pa identity.pub
+or the
+.Pa id_dsa.pub
 file and edit it.
 .Pp
-The options (if present) consists of comma-separated option
+The options (if present) consist of comma-separated option
 specifications.
 No spaces are permitted, except within double quotes.
 The following option specifications are supported:
@@ -675,6 +823,9 @@
 The command supplied by the user (if any) is ignored.
 The command is run on a pty if the connection requests a pty;
 otherwise it is run without a tty.
+Note that if you want a 8-bit clean channel,
+you must not request a pty or should specify
+.Cm no-pty .
 A quote may be included in the command by quoting it with a backslash.
 This option might be useful
 to restrict certain RSA keys to perform just a specific operation.
@@ -701,6 +852,15 @@
 authentication.
 .It Cm no-pty
 Prevents tty allocation (a request to allocate a pty will fail).
+.It Cm permitopen="host:port"
+Limit local 
+.Li ``ssh -L''
+port-forwading such that it may only connect to the specified host and
+port. Multiple 
+.Cm permitopen
+options may be applied seperated by commas. No pattern matching is 
+performed on the specified hostnames, they must be literal domains or 
+addresses.
 .El
 .Ss Examples
 1024 33 12121.\|.\|.\|312314325 ylo@foo.bar
@@ -708,6 +868,8 @@
 from="*.niksula.hut.fi,!pc.niksula.hut.fi" 1024 35 23.\|.\|.\|2334 ylo@niksula
 .Pp
 command="dump /home",no-pty,no-port-forwarding 1024 33 23.\|.\|.\|2323 backup.hut.fi
+.Pp
+permitopen="10.2.1.55:80",permitopen="10.2.1.56:25" 1024 33 23.\|.\|.\|2323
 .Sh SSH_KNOWN_HOSTS FILE FORMAT
 The
 .Pa /etc/ssh_known_hosts ,
@@ -718,7 +880,7 @@
 files contain host public keys for all known hosts.
 The global file should
 be prepared by the administrator (optional), and the per-user file is
-maintained automatically: whenever the user connects an unknown host
+maintained automatically: whenever the user connects from an unknown host
 its key is added to the per-user file.
 .Pp
 Each line in these files contains the following fields: hostnames,
@@ -770,30 +932,34 @@
 .Nm sshd .
 This file should be writable by root only, but it is recommended
 (though not necessary) that it be world-readable.
-.It Pa /etc/ssh_host_key
-Contains the private part of the host key.
-This file should only be owned by root, readable only by root, and not
+.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
+(SSH1, SSH2 DSA, and SSH2 RSA) host keys.
+These files should only be owned by root, readable only by root, and not
 accessible to others.
 Note that
 .Nm
 does not start if this file is group/world-accessible.
-.It Pa /etc/ssh_host_key.pub
-Contains the public part of the host key.
-This file should be world-readable but writable only by
+.It Pa /etc/ssh_host_key.pub, /etc/ssh_host_dsa_key.pub, /etc/ssh_host_rsa_key.pub
+There three files contain the public parts of the
+(SSH1, SSH2 DSA, and SSH2 RSA) host keys.
+These files should be world-readable but writable only by
 root.
-Its contents should match the private part.
-This file is not
-really used for anything; it is only provided for the convenience of
-the user so its contents can be copied to known hosts files.
-These two files are created using
+Their contents should match the respective private parts.
+These files are not
+really used for anything; they are provided for the convenience of
+the user so their contents can be copied to known hosts files.
+These files are created using
 .Xr ssh-keygen 1 .
+.It Pa /etc/primes
+Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
 .It Pa /var/run/sshd.pid
 Contains the process ID of the
 .Nm
 listening for connections (if there are several daemons running
 concurrently for different ports, this contains the pid of the one
 started last).
-The contents of this file are not sensitive; it can be world-readable.
+The content of this file is not sensitive; it can be world-readable.
 .It Pa $HOME/.ssh/authorized_keys
 Lists the RSA keys that can be used to log into the user's account.
 This file must be readable by root (which may on some machines imply
@@ -821,7 +987,7 @@
 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 the remote host is the one we intended to connect.
+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_hosts
 should be world-readable, and
@@ -860,7 +1026,7 @@
 .Pa .rhosts .
 However, this file is
 not used by rlogin and rshd, so using this permits access using SSH only.
-.Pa /etc/hosts.equiv
+.It Pa /etc/hosts.equiv
 This file is used during
 .Pa .rhosts
 authentication.
@@ -940,48 +1106,23 @@
 This can be used to specify
 machine-specific login-time initializations globally.
 This file should be writable only by root, and should be world-readable.
-.Sh AUTHOR
-OpenSSH
-is a derivative of the original (free) ssh 1.2.12 release by Tatu Ylonen,
-but with bugs removed and newer features re-added.
-Rapidly after the
-1.2.12 release, newer versions of the original ssh bore successively
-more restrictive licenses, and thus demand for a free version was born.
-.Pp
-This version of OpenSSH
-.Bl -bullet
-.It
-has all components of a restrictive nature (i.e., patents, see
-.Xr ssl 8 )
-directly removed from the source code; any licensed or patented components
-are chosen from
-external libraries.
-.It
-has been updated to support SSH protocol 1.5 and 2, making it compatible with
-all other SSH clients and servers.
-.It
-contains added support for
-.Xr kerberos 8
-authentication and ticket passing.
-.It
-supports one-time password authentication with
-.Xr skey 1 .
 .El
-.Pp
-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.
-.Pp
-The support for SSH protocol 2 was written by Markus Friedl.
+.Sh AUTHORS
+OpenSSH is a derivative of the original and free
+ssh 1.2.12 release by Tatu Ylonen.
+Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
+Theo de Raadt and Dug Song
+removed many bugs, re-added newer features and
+created OpenSSH.
+Markus Friedl contributed the support for SSH
+protocol versions 1.5 and 2.0.
 .Sh SEE ALSO
 .Xr scp 1 ,
+.Xr sftp 1 ,
+.Xr sftp-server 8 ,
 .Xr ssh 1 ,
 .Xr ssh-add 1 ,
 .Xr ssh-agent 1 ,
 .Xr ssh-keygen 1 ,
-.Xr ssl 8 ,
 .Xr rlogin 1 ,
 .Xr rsh 1