.\" (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_config.5,v 1.96 2008/07/02 02:24:18 djm Exp $
-.Dd $Mdocdate: July 2 2008 $
+.\" $OpenBSD: sshd_config.5,v 1.106 2009/04/21 15:13:17 stevesk Exp $
+.Dd $Mdocdate: April 21 2009 $
.Dt SSHD_CONFIG 5
.Os
.Sh NAME
This option is only available for protocol version 2.
By default, no banner is displayed.
.It Cm ChallengeResponseAuthentication
-Specifies whether challenge-response authentication is allowed.
-All authentication styles from
-.Xr login.conf 5
-are supported.
+Specifies whether challenge-response authentication is allowed (e.g. via
+PAM or though authentication styles supported in
+.Xr login.conf 5 )
The default is
.Dq yes .
.It Cm ChrootDirectory
to after authentication.
This path, and all its components, must be root-owned directories that are
not writable by any other user or group.
+After the chroot,
+.Xr sshd 8
+changes the working directory to the user's home directory.
.Pp
The path may contain the following tokens that are expanded at runtime once
the connecting user has been authenticated: %% is replaced by a literal '%',
The
.Cm ChrootDirectory
must contain the necessary files and directories to support the
-users' session.
+user's session.
For an interactive session this requires at least a shell, typically
.Xr sh 1 ,
and basic
For file transfer sessions using
.Dq sftp ,
no additional configuration of the environment is necessary if the
-in-process sftp server is used (see
-.Cm Subsystem
+in-process sftp server is used,
+though sessions which use logging do require
+.Pa /dev/log
+inside the chroot directory (see
+.Xr sftp-server 8
for details).
.Pp
The default is not to
.Dq cast128-cbc .
The default is:
.Bd -literal -offset 3n
-aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,
-arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr,
-aes192-ctr,aes256-ctr
+aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,
+aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,
+aes256-cbc,arcfour
.Ed
.It Cm ClientAliveCountMax
Sets the number of client alive messages (see below) which may be
The default is
.Dq yes .
Note that this option applies to protocol version 2 only.
+.It Cm GSSAPICredentialsPath
+If specified, the delegated GSSAPI credential is stored in the
+given path, overwriting any existing credentials.
+Paths can be specified with syntax similar to the AuthorizedKeysFile
+option (i.e., accepting %h and %u tokens).
+When using this option,
+setting 'GssapiCleanupCredentials no' is recommended,
+so logging out of one session
+doesn't remove the credentials in use by another session of
+the same user.
+Currently only implemented for the GSI mechanism.
+.It Cm GSIAllowLimitedProxy
+Specifies whether to accept limited proxy credentials for
+authentication.
+The default is
+.Dq no .
.It Cm GSSAPIStrictAcceptorCheck
Determines whether to be strict about the identity of the GSSAPI acceptor
a client authenticates against. If
and setting it to
.Dq no
may only work with recent Kerberos GSSAPI libraries.
-.It Cm GSSAPICredentialsPath
-If specified, the delegated GSSAPI credential is stored in the
-given path, overwriting any existing credentials.
-Paths can be specified with syntax similar to the AuthorizedKeysFile
-option (i.e., accepting %h and %u tokens).
-When using this option,
-setting 'GssapiCleanupCredentials no' is recommended,
-so logging out of one session
-doesn't remove the credentials in use by another session of
-the same user.
-Currently only implemented for the GSI mechanism.
-.It Cm GSIAllowLimitedProxy
-Specifies whether to accept limited proxy credentials for
-authentication.
-The default is
+.It Cm GSSAPIStoreCredentialsOnRekey
+Controls whether the user's GSSAPI credentials should be updated following a
+successful connection rekeying. This option can be used to accepted renewed
+or updated credentials from a compatible client. The default is
.Dq no .
.It Cm HostbasedAuthentication
Specifies whether rhosts or /etc/hosts.equiv authentication together
.Cm Match
keyword.
Available keywords are
+.Cm AllowAgentForwarding ,
.Cm AllowTcpForwarding ,
.Cm Banner ,
.Cm ChrootDirectory ,
.Cm MaxAuthTries ,
.Cm MaxSessions ,
.Cm PasswordAuthentication ,
+.Cm PermitEmptyPasswords ,
.Cm PermitOpen ,
.Cm PermitRootLogin ,
.Cm RhostsRSAAuthentication ,
.Cm RSAAuthentication ,
.Cm X11DisplayOffset ,
-.Cm X11Forwarding ,
+.Cm X11Forwarding
and
.Cm X11UseLocalHost .
.It Cm MaxAuthTries
as a non-root user.
The default is
.Dq no .
+.It Cm PermitPAMUserChange
+If set to
+.Dq yes
+this will enable PAM authentication to change the name of the user being
+authenticated. The default is
+.Dq no .
.It Cm UsePrivilegeSeparation
Specifies whether
.Xr sshd 8