Ubuntu Manpage: Config::Model::models::Ssh

Provided by: libconfig-model-openssh-perl_1.238-1_all

NAME

       Config::Model::models::Ssh - Configuration class Ssh

DESCRIPTION

       Configuration classes used by Config::Model

       Configuration class used by Config::Model to edit or validate ~/.ssh/config.

Elements

EnableSSHKeysign
Setting this option to 'yes' in the global client configuration file /etc/ssh/ssh_config enables the use
of the helper program ssh-keysign(8) during HostbasedAuthentication. See ssh-keysign(8)for more
information. Optional. Type boolean.

upstream_default value :
0

Host
The declarations make in 'parameters' are applied only to the hosts that match one of the patterns given
in pattern elements. A single '*' as a pattern can be used to provide global defaults for all hosts. The
host is the hostname argument given on the command line (i.e. the name is not converted to a
canonicalized host name before matching). Since the first obtained value for each parameter is used, more
host-specific declarations should be given near the beginning of the hash (which takes order into
account), and general defaults at the end. Optional. Type hash of node of class Ssh::HostElement .

AddressFamily
Specifies which address family to use when connecting. Optional. Type enum. choice: 'any', 'inet',
'inet6'.

upstream_default value :
any

BatchMode
If set to 'yes', passphrase/password querying will be disabled. In addition, the ServerAliveInterval
option will be set to 300 seconds by default. This option is useful in scripts and other batch jobs where
no user is present to supply the password, and where it is desirable to detect a broken network swiftly.
Optional. Type boolean.

upstream_default value :
0

BindAddress
Use the specified address on the local machine as the source address of the connection. Only useful on
systems with more than one address. Note that this option does not work if UsePrivilegedPort is set to
'yes'. Optional. Type uniline.

ChallengeResponseAuthentication
Specifies whether to use challenge-response authentication. Optional. Type boolean.

upstream_default value :
1

CheckHostIP
If enabled, ssh(1) will additionally check the host IP address in the known_hosts file. This allows ssh
to detect if a host key changed due to DNS spoofing. If disbled, the check will not be executed.
Optional. Type boolean.

upstream_default value :
1

Cipher
Specifies the cipher to use for encrypting the session in protocol version 1. "des" is only supported in
the ssh(1) client for interoperability with legacy protocol 1 implementations that do not support the
3des cipher. Its use is strongly discouraged due to cryptographic weaknesses. Optional. Type enum.
choice: 'blowfish', '3des', 'des'.

upstream_default value :
3des

Ciphers
Specifies the ciphers allowed for protocol version 2 in order of preference. Multiple ciphers must be
comma-separated. If the specified value begins with a X+X character, then the specified ciphers will be
appended to the default set instead of replacing them. If the specified value begins with a X-X
character, then the specified ciphers (including wildcards) will be removed from the default set instead
of replacing them.

The supported ciphers are:

3des-cbc
aes128-cbc
aes192-cbc
aes256-cbc
aes128-ctr
aes192-ctr
aes256-ctr
aes128-gcm@openssh.com
aes256-gcm@openssh.com
arcfour
arcfour128
arcfour256
blowfish-cbc
cast128-cbc
chacha20-poly1305@openssh.com

The default is:

chacha20-poly1305@openssh.com,
aes128-ctr,aes192-ctr,aes256-ctr,
aes128-gcm@openssh.com,aes256-gcm@openssh.com,
aes128-cbc,aes192-cbc,aes256-cbc

The list of available ciphers may also be obtained using "ssh -Q cipher" Optional. Type uniline.

ClearAllForwardings
Specifies that all local, remote, and dynamic port forwardings specified in the configuration files or on
the command line be cleared. This option is primarily useful when used from the ssh(1) command line to
clear port forwardings set in configuration files, and is automatically set by scp(1) and sftp(1).
Optional. Type boolean.

upstream_default value :
0

Compression
Specifies whether to use compression. Optional. Type boolean.

upstream_default value :
0

CompressionLevel
Optional. Type integer.

upstream_default value :
6

ConnectionAttempts
Specifies the number of tries (one per second) to make before exiting. The argument must be an integer.
This may be useful in scripts if the connection sometimes fails. Optional. Type integer.

upstream_default value :
1

ConnectTimeout
Specifies the timeout (in seconds) used when connecting to the SSH server, instead of using the default
system TCP timeout. This value is used only when the target is down or really unreachable, not when it
refuses the connection. Optional. Type integer.

ControlMaster
Enables the sharing of multiple sessions over a single network connection. When set to 'yes', ssh(1) will
listen for connections on a control socket specified using the ControlPath argument. Additional sessions
can connect to this socket using the same ControlPath with ControlMaster set to 'no' (the default). These
sessions will try to reuse the master instance's network connection rather than initiating new ones, but
will fall back to connecting normally if the control socket does not exist, or is not listening.

Setting this to 'ask' will cause ssh to listen for control connections, but require confirmation using
the SSH_ASKPASS program before they are accepted (see ssh-add(1) for details). If the ControlPath cannot
be opened, ssh will continue without connecting to a master instance.

X11 and ssh-agent(1) forwarding is supported over these multiplexed connections, however the display and
agent forwarded will be the one belonging to the master connection i.e. it is not pos sible to forward
multiple displays or agents.

Two additional options allow for opportunistic multiplexing: try to use a master connection but fall back
to creating a new one if
one does not already exist. These options are: 'auto' and 'autoask'. The latter requires confirmation
like the 'ask' option. Optional. Type enum. choice: 'no', 'yes', 'ask', 'auto', 'autoask'.

upstream_default value :
no

ControlPath
Specify the path to the control socket used for connection sharing as described in the ControlMaster
section above or the string 'none' to disable connection sharing. In the path, '%l' will be substituted
by the local host name, '%h' will be substituted by the target host name, '%p' the port, and '%r' by the
remotelogin username. It is recommended that any ControlPath used for opportunistic connection sharing
include at least %h, %p, and %r. This ensures that shared connections are uniquely identified.
Optional. Type uniline.

ControlPersist - persists the master connection in the background
When used in conjunction with ControlMaster, specifies that the master connection should remain open in
the background (waiting for future client connections) after the initial client connection has been
closed. If set to ``no'', then the master connection will not be placed into the background, and will
close as soon as the initial client connection is closed. If set to ``yes'', then the master connection
will remain in the background indef- initely (until killed or closed via a mechanism such as the ssh(1)
``-O exit'' option). If set to a time in seconds, or a time in any of the formats documented in
sshd_config(5), then the backgrounded master connection will automatically terminate after it has
remained idle (with no client connections) for the specified time. Optional. Type uniline.

DynamicForward
Specifies that a TCP port on the local machine be forwarded over the secure channel, and the application
protocol is then used to determine where to connect to from the remote machine.

The argument must be [bind_address:]port. IPv6 addresses can be specified by enclosing addresses in
square brackets or by using an alternative syntax: [bind_address/]port. By default, the local port is
bound in accordance with the GatewayPorts setting. However, an explicit bind_address may be used to bind
the connection to a specific address. The bind_address of 'localhost' indicates that the listening port
be bound for local use only, while an empty address or '*' indicates that the port should be available
from all interfaces.

Currently the SOCKS4 and SOCKS5 protocols are supported, and ssh(1) will act as a SOCKS server. Multiple
forwardings may be specified, and additional forwardings can be given on the command line. Only the
superuser can forward privileged ports. Optional. Type list of uniline.

EscapeChar
Sets the escape character (default: '~'). The escape character can also be set on the command line. The
argument should be a single character, '^' followed by a letter, or 'none' to disable the escape
character entirely (making the connection transparent for binary data). Optional. Type uniline.

upstream_default value :
~

ExitOnForwardFailure
Specifies whether ssh(1) should terminate the connection if it cannot set up all requested dynamic,
tunnel, local, and remote port forwardings. Optional. Type boolean.

upstream_default value :
0

ForwardAgent
Specifies whether the connection to the authentication agent (if any) will be forwarded to the remote
machine.

Agent forwarding should be enabled with caution. Users with the ability to bypass file permissions on
the remote host (for the agent's Unix-domain socket) can access the local agent through the forwarded
connection. An attacker cannot obtain key material from the agent, however they can perform operations
on the keys that enable them to authenticate using the identities loaded into the agent. Optional. Type
boolean.

upstream_default value :
0

ForwardX11
Specifies whether X11 connections will be automatically redirected over the secure channel and DISPLAY
set.

X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the
remote host (for the user's X11 authorization database) can access the local X11 dis play through the
forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring if
the ForwardX11Trusted option is also enabled. Optional. Type boolean.

upstream_default value :
0

ForwardX11Timeout - timeout for untrusted X11 forwarding
Specify a timeout for untrusted X11 forwarding using the format described in the TIME FORMATS section of
sshd_config(5). X11 connections received by ssh(1) after this time will be refused. The default is to
disable untrusted X11 forwarding after twenty minutes has elapsed. Optional. Type uniline.

ForwardX11Trusted
If this option is set, remote X11 clients will have full access to the original X11 display.

If this option is not set, remote X11 clients will be considered untrusted and prevented from stealing or
tampering with data belonging to trusted X11 clients. Furthermore, the xauth(1) token used for the
session will be set to expire after 20 minutes. Remote clients will be refused access after this time.

See the X11 SECURITY extension specification for full details on the restrictions imposed on untrusted
clients. Optional. Type boolean.

upstream_default value :
0

GatewayPorts
Specifies whether remote hosts are allowed to connect to local forwarded ports. By default, ssh(1) binds
local port forwardings to the loopback address. This prevents other remote hosts from connecting to
forwarded ports. GatewayPorts can be used to specify that ssh should bind local port forwardings to the
wildcard address, thus allowing remote hosts to connect to forwarded ports. Optional. Type boolean.

upstream_default value :
0

GlobalKnownHostsFile
Specifies a file to use for the global host key database. Optional. Type uniline.

upstream_default value :
/etc/ssh/ssh_known_hosts

GSSAPIAuthentication
Specifies whether user authentication based on GSSAPI is allowed. Note that this option applies to
protocol version 2 only. Optional. Type boolean.

upstream_default value :
0

GSSAPIKeyExchange
Specifies whether key exchange based on GSSAPI may be used. When using GSSAPI key exchange the server
need not have a host key. Note that this option applies to protocol version 2 only. Optional. Type
boolean.

upstream_default value :
0

GSSAPIClientIdentity
If set, specifies the GSSAPI client identity that ssh should use when connecting to the server. The
default is unset, which means that the default identity will be used. Optional. Type uniline.

GSSAPIServerIdentity
If set, specifies the GSSAPI server identity that ssh should expect when connecting to the server. The
default is unset, which means that the expected GSSAPI server identity will be determined from the target
hostname. Optional. Type uniline.

GSSAPIDelegateCredentials
Forward (delegate) credentials to the server. Note that this option applies to protocol version 2
connections using GSSAPI. Optional. Type boolean.

upstream_default value :
0

GSSAPIRenewalForcesRekey
If set to "yes" then renewal of the client's GSSAPI credentials will force the rekeying of the ssh
connection. With a compatible server, this can delegate the renewed credentials to a session on the
server. Optional. Type boolean.

upstream_default value :
0

GSSAPITrustDns
Set to "yes" to indicate that the DNS is trusted to securely canonicalize the name of the host being
connected to. If "no", the hostname entered on the command line will be passed untouched to the GSSAPI
library. This option only applies to protocol version 2 connections using GSSAPI. Optional. Type
boolean.

upstream_default value :
0

HashKnownHosts
Indicates that ssh(1) should hash host names and addresses when they are added to ~/.ssh/known_hosts.
These hashed names may be used normally by ssh(1) and sshd(8), but they do not reveal identifying
information should the file's contents be disclosed. Note that existing names and addresses in known
hosts files will not be converted automatically, but may be manually hashed using ssh-keygen(1).
Optional. Type boolean.

upstream_default value :
0

HostbasedAuthentication
Specifies whether to try rhosts based authentication with public key authentication. This option applies
to protocol version 2 only and is similar to RhostsRSAAuthentication. Optional. Type boolean.

upstream_default value :
0

HostKeyAlgorithms
Specifies the protocol version 2 host key algorithms that the client wants to use in order of preference.
Optional. Type check_list. choice: 'ssh-rsa', 'ssh-dss'.

HostKeyAlias
Specifies an alias that should be used instead of the real host name when looking up or saving the host
key in the host key database files. This option is useful for tunneling SSH connections or for multiple
servers running on a single host. Optional. Type uniline.

HostName
Specifies the real host name to log into. This can be used to specify nicknames or abbreviations for
hosts. The default is the name given on the command line. Numeric IP addresses are also permitted (both
on the command line and in HostName specifications). Optional. Type uniline.

IdentitiesOnly
Specifies that ssh(1) should only use the authentication identity files configured in the ssh_config
files, even if ssh-agent(1) offers more identities. This option is intended for situations where ssh-
agent offers many different identities. Optional. Type boolean.

upstream_default value :
0

IdentityFile
Specifies a file from which the user's RSA or DSA authentication identity is read. The default is
~/.ssh/identity for protocol version 1, and ~/.ssh/id_rsa and ~/.ssh/id_dsa for protocol version 2.
Additionally, any identities represented by the authentication agent will be used for authentication.

The file name may use the tilde syntax to refer to a user's home directory or one of the following escape
characters: '%d' (local user's home directory), '%u' (local user name), '%l' (local host name), '%h'
(remote host name) or '%r' (remote user name).

It is possible to have multiple identity files specified in con figuration files; all these identities
will be tried in sequence. Optional. Type list of uniline.

IPQoS - IPv4 type-of-service or DSCP class for the connection.
Specifies the IPv4 type-of-service or DSCP class for the connection. Accepted values are "af11", "af12",
"af13", "af21", "af22", "af23", "af31", "af32", "af33", "af41", "af42", "af43", "cs0", "cs1", "cs2",
"cs3", "cs4", "cs5", "cs6", "cs7", "ef", "lowdelay", "throughput", "reliability", or a numeric value.
This option may take one or two arguments, separated by whitespace. If one argument is specified, it is
used as the packet class unconditionally. If two values are specified, the first is automatically
selected for interactive sessions and the second for non-interactive sessions. The default is "lowdelay"
for interactive sessions and "throughput" for non-interactive sessions. Optional. Type uniline.

upstream_default value :
lowdelay throughput

KbdInteractiveAuthentication
Specifies whether to use keyboard-interactive authentication. Optional. Type boolean.

upstream_default value :
1

KbdInteractiveDevices
Specifies the list of methods to use in keyboard-interactive authentication. Multiple method names must
be comma-separated. The default is to use the server specified list. The methods available vary depending
on what the server supports. For an OpenSSH server, it may be zero or more of: 'bsdauth', 'pam', and
'skey'. Optional. Type list of uniline.

KexAlgorithms
Specifies the available KEX (Key Exchange) algorithms. Optional. Type check_list. choice:
'ecdh-sha2-nistp256', 'ecdh-sha2-nistp384', 'ecdh-sha2-nistp521', 'diffie-hellman-group-exchange-sha256',
'diffie-hellman-group-exchange-sha1', 'diffie-hellman-group14-sha1', 'diffie-hellman-group1-sha1'.

LocalForward - Local port forwarding
Specifies that a TCP port on the local machine be forwarded over the secure channel to the specified host
and port from the remote machine. The first argument must be [bind_address:]port and the second argument
must be host:hostport.

IPv6 addresses can be specified by enclosing addresses in square brackets or by using an alternative
syntax: [bind_address/]port and host/hostport.

Multiple forwardings may be specified, and additional forwardings can be given on the command line. Only
the superuser can forward privileged ports.

By default, the local port is bound in accordance with the GatewayPorts setting. However, an explicit
bind_address may be used to bind the connection to a specific address. The bind_address of "localhost"
indicates that the listening port be bound for local use only, while an empty address or '*' indicates
that the port should be available from all interfaces.

Example:
LocalForward 20000 192.168.0.66:80 . Optional. Type list of node of class Ssh::PortForward .

LogLevel
Gives the verbosity level that is used when logging messages from ssh(1). The possible values are:
SILENT, QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. The default is INFO.
DEBUG and DEBUG1 are equivalent. DEBUG2 and DEBUG3 each specify higher levels of verbose output.
Optional. Type enum. choice: 'SILENT', 'QUIET', 'FATAL', 'ERROR', 'INFO', 'VERBOSE', 'DEBUG', 'DEBUG1',
'DEBUG2', 'DEBUG3'.

upstream_default value :
INFO

MACs
Specifies the MAC (message authentication code) algorithms in order of preference. The MAC algorithm is
used in protocol version 2 for data integrity protection. Optional. Type check_list. choice: 'hmac-md5',
'hmac-sha1', 'umac-64@openssh.com', 'hmac-ripemd160', 'hmac-sha1-96', 'hmac-md5-96'.

NoHostAuthenticationForLocalhost
This option can be used if the home directory is shared across machines. In this case localhost will
refer to a different machine on each of the machines and the user will get many warn ings about changed
host keys. However, this option disables host authentication for localhost. The default is to check the
host key for localhost. Optional. Type boolean.

upstream_default value :
0

NumberOfPasswordPrompts
Specifies the number of password prompts before giving up. Optional. Type integer.

upstream_default value :
3

PasswordAuthentication
Specifies whether to use password authentication. Optional. Type boolean.

upstream_default value :
1

PermitLocalCommand
Allow local command execution via the LocalCommand option or using the !command escape sequence in
ssh(1). Optional. Type boolean.

upstream_default value :
0

LocalCommand
Specifies a command to execute on the local machine after successfully connecting to the server. The
command string extends to the end of the line, and is executed with the user's shell. The following
escape character substitutions will be performed: '%d' (local user's home directory), '%h' (remote host
name), '%l' (local host name), '%n' (host name as provided on the command line), '%p' (remote port), '%r'
(remote user name) or '%u' (local user name). This directive is ignored unless PermitLocalCommand has
been enabled. Optional. Type uniline.

PKCS11Provider
Specifies which PKCS#11 provider to use. The argument to this keyword is the PKCS#11 shared library
ssh(1) should use to communicate with a PKCS#11 token providing the user's private RSA key. Optional.
Type uniline.

Port
Specifies the port number to connect on the remote host. Optional. Type integer.

upstream_default value :
22

PreferredAuthentications
Specifies the order in which the client should try protocol 2 authentication methods. This allows a
client to prefer one method (e.g. keyboard-interactive) over another method (e.g. password). Optional.
Type check_list. choice: 'gssapi-with-mic', 'hostbased', 'publickey', 'keyboard-interactive', 'password'.

Protocol
Specifies the protocol versions ssh(1) should support in order of preference. The default is "2,1".
This means that ssh tries version 2 and falls back to version 1 if version 2 is not available. Optional.
Type check_list. choice: '2', '1'.

ProxyCommand
Specifies the command to use to connect to the server. The command string extends to the end of the line,
and is executed with the user's shell. In the command string, '%h' will be substi tuted by the host name
to connect and '%p' by the port. The com mand can be basically anything, and should read from its
standard input and write to its standard output. It should eventually connect an sshd(8) server running
on some machine, or execute sshd -i somewhere. Host key management will be done using the HostName of the
host being connected (defaulting to the name typed by the user). Setting the command to "none" disables
this option entirely. Note that CheckHostIP is not available for connects with a proxy command.

This directive is useful in conjunction with nc(1) and its proxy support. For example, the following
directive would connect via an HTTP proxy at 192.0.2.0:

ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p. I< Optional. Type uniline. >

PubkeyAuthentication
Specifies whether to try public key authentication. This option applies to protocol version 2 only.
Optional. Type boolean.

upstream_default value :
1

RekeyLimit
Specifies the maximum amount of data that may be transmitted before the session key is renegotiated. The
argument is the number of bytes, with an optional suffix of 'K', 'M', or 'G' to indicate Kilobytes,
Megabytes, or Gigabytes, respectively. The default is between '1G' and '4G', depending on the cipher.
This option applies to protocol version 2 only. Optional. Type uniline.

RemoteForward - remote port forward to local
Specifies that a TCP port on the remote machine be forwarded over the secure channel to the specified
host and port from the local machine. Multiple forwardings may be specified, and additional forwardings
can be given on the command line. Only the superuser can forward privileged ports.

If the bind_address is not specified, the default is to only bind to loopback addresses. If the
bind_address is '*' or an empty string, then the forwarding is requested to listen on all inter faces.
Specifying a remote bind_address will only succeed if the server's GatewayPorts option is enabled (see
sshd_config(5)). Optional. Type list of node of class Ssh::PortForward .

RequestTTY
Specifies whether to request a pseudo-tty for the session. This option mirrors the -t and -T flags for
"ssh". Optional. Type enum. choice: 'yes', 'no', 'force', 'auto'.

Here are some explanations on the possible values:

'auto'
request a TTY when opening a login session

'force'
always request a TTY

'no'
never request a TTY

'yes'
always request a TTY when standard input is a TTY

RhostsRSAAuthentication
Specifies whether to try rhosts based authentication with RSA host authentication. This option applies to
protocol version 1 only and requires ssh(1) to be setuid root. Optional. Type boolean.

upstream_default value :
0

RSAAuthentication
Specifies whether to try RSA authentication. RSA authentication will only be attempted if the identity
file exists, or an authentication agent is running. Note that this option applies to protocol version 1
only. Optional. Type boolean.

upstream_default value :
1

SendEnv
Specifies what variables from the local environ(7) should be sent to the server. Note that environment
passing is only supported for protocol 2. The server must also support it, and the server must be
configured to accept these environment variables. Refer to AcceptEnv in sshd_config(5) for how to
configure the server. Variables are specified by name, which may contain wildcard char acters. Multiple
environment variables may be separated by whitespace or spread across multiple SendEnv directives. The
default is not to send any environment variables.

See PATTERNS in ssh_config(5) for more information on patterns. Optional. Type list of uniline.

ServerAliveCountMax
Sets the number of server alive messages (see below) which may be sent without ssh(1) receiving any
messages back from the server. If this threshold is reached while server alive messages are being sent,
ssh will disconnect from the server, terminating the session. It is important to note that the use of
server alive messages is very different from TCPKeepAlive. The server alive messages are sent through
the encrypted channel and there fore will not be spoofable. The TCP keepalive option enabled by
TCPKeepAlive is spoofable. The server alive mechanism is valuable when the client or server depend on
knowing when a connec tion has become inactive.

The default value is 3. If, for example, ServerAliveInterval is set to 15 and ServerAliveCountMax is left
at the default, if the server becomes unresponsive, ssh will disconnect after approximately 45 seconds.
This option applies to protocol version 2 only; in protocol version 1 there is no mechanism to request a
response from the server to the server alive messages, so disconnection is the responsibility of the TCP
stack. Optional. Type integer.

upstream_default value :
3

ServerAliveInterval
Sets a timeout interval in seconds after which if no data has been received from the server, ssh(1) will
send a message through the encrypted channel to request a response from the server. The default is 0,
indicating that these messages will not be sent to the server, or 300 if the BatchMode option is set.
This option applies to protocol version 2 only. ProtocolKeepAlives and SetupTimeOut are Debian-specific
compatibility aliases for this option. Optional. Type integer.

upstream_default value :
0

SmartcardDevice
Specifies which smartcard device to use. The argument to this keyword is the device ssh(1) should use to
communicate with a smartcard used for storing the user's private RSA key. By default, no device is
specified and smartcard support is not activated. Optional. Type uniline.

StrictHostKeyChecking
If this flag is set to "yes", ssh(1) will never automatically add host keys to the ~/.ssh/known_hosts
file, and refuses to connect to hosts whose host key has changed. This provides maximum protection
against trojan horse attacks, though it can be annoying when the /etc/ssh/ssh_known_hosts file is poorly
maintained or when connections to new hosts are frequently made. This option forces the user to manually
add all new hosts. If this flag is set to "no", ssh will automatically add new host keys to the user
known hosts files. If this flag is set to "ask", new host keys will be added to the user known host
files only after the user has confirmed that is what they really want to do, and ssh will refuse to
connect to hosts whose host key has changed. The host keys of known hosts will be verified automatically
in all cases. The argument must be "yes", "no", or "ask". The default is "ask". Optional. Type enum.
choice: 'yes', 'no', 'ask'.

upstream_default value :
ask

TCPKeepAlive
Specifies whether the system should send TCP keepalive messages to the other side. If they are sent,
death of the connection or crash of one of the machines will be properly noticed. This option only uses
TCP keepalives (as opposed to using ssh level keepalives), so takes a long time to notice when the
connection dies. As such, you probably want the ServerAliveInterval option as well. However, this means
that connections will die if the route is down temporarily, and some people find it annoying. The default
is "yes" (to send TCP keepalive messages), and the client will notice if the network goes down or the
remote host dies. This is important in scripts, and many users want it too.

To disable TCP keepalive messages, the value should be set to "no". Optional. Type boolean.

upstream_default value :
1

Tunnel
Request tun(4) device forwarding between the client and the server. The argument must be "yes", "point-
to-point" (layer 3), "ethernet" (layer 2), or "no". Specifying "yes" requests the default tunnel mode,
which is "point-to-point". The default is "no". Optional. Type enum. choice: 'yes', 'point-to-point',
'ethernet', 'no'.

upstream_default value :
no

TunnelDevice
Specifies the tun(4) devices to open on the client (local_tun) and the server (remote_tun).

The argument must be local_tun[:remote_tun]. The devices may be specified by numerical ID or the keyword "any", which uses the next available tunnel device. If remote_tun is not specified, it defaults to "any". The default is "any:any". I< Optional. Type uniline. >

upstream_default value :
any:any

UseBlacklistedKeys
Specifies whether ssh(1) should use keys recorded in its blacklist of known-compromised keys (see
ssh-vulnkey(1)) for authentication. If "yes", then attempts to use compromised keys for authentication
will be logged but accepted. It is strongly recommended that this be used only to install new authorized
keys on the remote system, and even then only with the utmost care. If "no", then attempts to use
compromised keys for authentication will be prevented. The default is "no". Optional. Type boolean.

upstream_default value :
0

UsePrivilegedPort
Specifies whether to use a privileged port for outgoing connections. The argument must be "yes" or "no".
The default is "no". If set to "yes", ssh(1) must be setuid root. Note that this option must be set to
"yes" for RhostsRSAAuthentication with older servers. Optional. Type boolean.

upstream_default value :
0

User
Specifies the user to log in as. This can be useful when a dif ferent user name is used on different
machines. This saves the trouble of having to remember to give the user name on the command line.
Optional. Type uniline.

UserKnownHostsFile
Specifies a file to use for the user host key database instead of ~/.ssh/known_hosts. Optional. Type
uniline.

VerifyHostKeyDNS
Specifies whether to verify the remote key using DNS and SSHFP resource records. If this option is set
to "yes", the client will implicitly trust keys that match a secure fingerprint from DNS. Insecure
fingerprints will be handled as if this option was set to "ask". If this option is set to "ask",
information on fingerprint match will be displayed, but the user will still need to confirm new host keys
according to the StrictHostKeyChecking option. The argument must be "yes", "no", or "ask". The default
is "no". Note that this option applies to protocol version 2 only. See also VERIFYING HOST KEYS in
ssh(1). Optional. Type enum. choice: 'yes', 'no', 'ask'.

upstream_default value :
no

VisualHostKey
If this flag is set to "yes", an ASCII art representation of the remote host key fingerprint is printed
additionally to the hex fingerprint string. If this flag is set to "no", only the hex fingerprint string
will be printed. The default is "no". Optional. Type boolean.

upstream_default value :
0

XAuthLocation
Specifies the full pathname of the xauth(1) program. The default is /usr/bin/X11/xauth. Optional. Type
uniline.

upstream_default value :
/usr/X11R6/bin/xauth

UseRsh
This parameter is now ignored by Ssh. Deprecated Optional. Type uniline.

FallBackToRsh
This parameter is now ignored by Ssh. Deprecated Optional. Type uniline.

IgnoreUnknown
Specifies a pattern-list of unknown options to be ignored if they are encountered in configuration
parsing. This may be used to suppress errors if ssh_config contains options that are unrecognised by
ssh(1). It is recommended that IgnoreUnknown be listed early in the configuration file as it will not be
applied to unknown options that appear before it. Optional. Type uniline.

AUTHOR

       Dominique Dumont <ddumon at cpan.org>

COPYRIGHT

       2009-2013 Dominique Dumont

LICENSE

       LGPL2

perl v5.26.1                                       2017-10-10                    Config::Model::models::Ssh(3pm)

NAME

DESCRIPTION

Elements

SEE ALSO

AUTHOR

COPYRIGHT

LICENSE