version 1.29, 2004/03/08 10:18:57 |
version 1.29.2.2, 2005/03/10 17:15:05 |
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keywords and their meanings are as follows (note that |
keywords and their meanings are as follows (note that |
keywords are case-insensitive and arguments are case-sensitive): |
keywords are case-insensitive and arguments are case-sensitive): |
.Bl -tag -width Ds |
.Bl -tag -width Ds |
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.It Cm AcceptEnv |
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Specifies what environment variables sent by the client will be copied into |
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the session's |
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.Xr environ 7 . |
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See |
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.Cm SendEnv |
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in |
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.Xr ssh_config 5 |
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for how to configure the client. |
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Note that environment passing is only supported for protocol 2. |
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Variables are specified by name, which may contain the wildcard characters |
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.Ql \&* |
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and |
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.Ql \&? . |
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Multiple environment variables may be separated by whitespace or spread |
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across multiple |
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.Cm AcceptEnv |
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directives. |
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Be warned that some environment variables could be used to bypass restricted |
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user environments. |
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For this reason, care should be taken in the use of this directive. |
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The default is not to accept any environment variables. |
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.It Cm AddressFamily |
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Specifies which address family should be used by |
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.Nm sshd . |
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Valid arguments are |
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.Dq any , |
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.Dq inet |
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(use IPv4 only) or |
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.Dq inet6 |
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(use IPv6 only). |
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The default is |
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.Dq any . |
.It Cm AllowGroups |
.It Cm AllowGroups |
This keyword can be followed by a list of group name patterns, separated |
This keyword can be followed by a list of group name patterns, separated |
by spaces. |
by spaces. |
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wildcards in the patterns. |
wildcards in the patterns. |
Only group names are valid; a numerical group ID is not recognized. |
Only group names are valid; a numerical group ID is not recognized. |
By default, login is allowed for all groups. |
By default, login is allowed for all groups. |
.Pp |
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.It Cm AllowTcpForwarding |
.It Cm AllowTcpForwarding |
Specifies whether TCP forwarding is permitted. |
Specifies whether TCP forwarding is permitted. |
The default is |
The default is |
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Note that disabling TCP forwarding does not improve security unless |
Note that disabling TCP forwarding does not improve security unless |
users are also denied shell access, as they can always install their |
users are also denied shell access, as they can always install their |
own forwarders. |
own forwarders. |
.Pp |
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.It Cm AllowUsers |
.It Cm AllowUsers |
This keyword can be followed by a list of user name patterns, separated |
This keyword can be followed by a list of user name patterns, separated |
by spaces. |
by spaces. |
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If the pattern takes the form USER@HOST then USER and HOST |
If the pattern takes the form USER@HOST then USER and HOST |
are separately checked, restricting logins to particular |
are separately checked, restricting logins to particular |
users from particular hosts. |
users from particular hosts. |
.Pp |
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.It Cm AuthorizedKeysFile |
.It Cm AuthorizedKeysFile |
Specifies the file that contains the public keys that can be used |
Specifies the file that contains the public keys that can be used |
for user authentication. |
for user authentication. |
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authentication is allowed. |
authentication is allowed. |
This option is only available for protocol version 2. |
This option is only available for protocol version 2. |
By default, no banner is displayed. |
By default, no banner is displayed. |
.Pp |
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.It Cm ChallengeResponseAuthentication |
.It Cm ChallengeResponseAuthentication |
Specifies whether challenge response authentication is allowed. |
Specifies whether challenge response authentication is allowed. |
All authentication styles from |
All authentication styles from |
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.It Cm Ciphers |
.It Cm Ciphers |
Specifies the ciphers allowed for protocol version 2. |
Specifies the ciphers allowed for protocol version 2. |
Multiple ciphers must be comma-separated. |
Multiple ciphers must be comma-separated. |
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The supported ciphers are |
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.Dq 3des-cbc , |
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.Dq aes128-cbc , |
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.Dq aes192-cbc , |
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.Dq aes256-cbc , |
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.Dq aes128-ctr , |
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.Dq aes192-ctr , |
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.Dq aes256-ctr , |
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.Dq arcfour , |
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.Dq blowfish-cbc , |
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and |
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.Dq cast128-cbc . |
The default is |
The default is |
.Pp |
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.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,aes128-ctr,aes192-ctr,aes256-ctr'' |
aes192-cbc,aes256-cbc,aes128-ctr,aes192-ctr,aes256-ctr'' |
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wildcards in the patterns. |
wildcards in the patterns. |
Only group names are valid; a numerical group ID is not recognized. |
Only group names are valid; a numerical group ID is not recognized. |
By default, login is allowed for all groups. |
By default, login is allowed for all groups. |
.Pp |
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.It Cm DenyUsers |
.It Cm DenyUsers |
This keyword can be followed by a list of user name patterns, separated |
This keyword can be followed by a list of user name patterns, separated |
by spaces. |
by spaces. |
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.Cm GatewayPorts |
.Cm GatewayPorts |
can be used to specify that |
can be used to specify that |
.Nm sshd |
.Nm sshd |
should bind remote port forwardings to the wildcard address, |
should allow remote port forwardings to bind to non-loopback addresses, thus |
thus allowing remote hosts to connect to forwarded ports. |
allowing other hosts to connect. |
The argument must be |
The argument may be |
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.Dq no |
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to force remote port forwardings to be available to the local host only, |
.Dq yes |
.Dq yes |
or |
to force remote port forwardings to bind to the wildcard address, or |
.Dq no . |
.Dq clientspecified |
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to allow the client to select the address to which the forwarding is bound. |
The default is |
The default is |
.Dq no . |
.Dq no . |
.It Cm GSSAPIAuthentication |
.It Cm GSSAPIAuthentication |
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Multiple algorithms must be comma-separated. |
Multiple algorithms must be comma-separated. |
The default is |
The default is |
.Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 . |
.Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 . |
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.It Cm MaxAuthTries |
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Specifies the maximum number of authentication attempts permitted per |
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connection. |
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Once the number of failures reaches half this value, |
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additional failures are logged. |
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The default is 6. |
.It Cm MaxStartups |
.It Cm MaxStartups |
Specifies the maximum number of concurrent unauthenticated connections to the |
Specifies the maximum number of concurrent unauthenticated connections to the |
.Nm sshd |
.Nm sshd |
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The default is |
The default is |
.Dq no . |
.Dq no . |
.It Cm PermitRootLogin |
.It Cm PermitRootLogin |
Specifies whether root can login using |
Specifies whether root can log in using |
.Xr ssh 1 . |
.Xr ssh 1 . |
The argument must be |
The argument must be |
.Dq yes , |
.Dq yes , |
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.Pp |
.Pp |
If this option is set to |
If this option is set to |
.Dq no |
.Dq no |
root is not allowed to login. |
root is not allowed to log in. |
.It Cm PermitUserEnvironment |
.It Cm PermitUserEnvironment |
Specifies whether |
Specifies whether |
.Pa ~/.ssh/environment |
.Pa ~/.ssh/environment |
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.It Cm PrintLastLog |
.It Cm PrintLastLog |
Specifies whether |
Specifies whether |
.Nm sshd |
.Nm sshd |
should print the date and time when the user last logged in. |
should print the date and time of the last user login when a user logs |
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in interactively. |
The default is |
The default is |
.Dq yes . |
.Dq yes . |
.It Cm PrintMotd |
.It Cm PrintMotd |