Provided by: libconfig-model-openssh-perl_2.9.4.1-1_all bug

NAME

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

DESCRIPTION

       Configuration classes used by Config::Model

       This configuration class was generated from ssh_system documentation.  by parse-man.pl
       <https://github.com/dod38fr/config-model-openssh/contrib/parse-man.pl>

Elements

   Host
       Restricts the following declarations (up to the next Host or Match keyword) to be only for
       those hosts that match one of the patterns given after the keyword. If more than one
       pattern is provided, they should be separated by whitespace. A single '*' as a pattern can
       be used to provide global defaults for all hosts. The host is usually the hostname
       argument given on the command line (see the CanonicalizeHostname keyword for exceptions).

       A pattern entry may be negated by prefixing it with an exclamation mark ('!' ) If a
       negated entry is matched, then the Host entry is ignored, regardless of whether any other
       patterns on the line match. Negated matches are therefore useful to provide exceptions for
       wildcard matches.

       See PATTERNS for more information on patterns.  Optional. Type hash of node of class
       Ssh::HostElement .

   AddKeysToAgent
       Specifies whether keys should be automatically added to a running ssh-agent1.  If this
       option is set to yes and a key is loaded from a file, the key and its passphrase are added
       to the agent with the default lifetime, as if by ssh-add1. If this option is set to ask
       ssh(1) will require confirmation using the SSH_ASKPASS program before adding a key (see
       ssh-add1 for details). If this option is set to confirm each use of the key must be
       confirmed, as if the -c option was specified to ssh-add1. If this option is set to no no
       keys are added to the agent. Alternately, this option may be specified as a time interval
       using the format described in the TIME FORMATS section of sshd_config5 to specify the
       key's lifetime in ssh-agent1, after which it will automatically be removed. The argument
       must be no (the default), yes confirm (optionally followed by a time interval), ask or a
       time interval.  Optional. Type enum. choice: 'ask', 'confirm', 'no', 'yes'.

       upstream_default value :
           no

   AddressFamily
       Specifies which address family to use when connecting. Valid arguments are any (the
       default), inet (use IPv4 only), or inet6 (use IPv6 only).  Optional. Type enum. choice:
       'any', 'inet', 'inet6'.

       upstream_default value :
           any

   BatchMode
       If set to yes user interaction such as password prompts and host key confirmation requests
       will be disabled. In addition, the ServerAliveInterval option will be set to 300 seconds
       by default (Debian-specific). This option is useful in scripts and other batch jobs where
       no user is present to interact with ssh(1), and where it is desirable to detect a broken
       network swiftly.  The argument must be yes or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   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.  Optional. Type uniline.

   BindInterface
       Use the address of the specified interface on the local machine as the source address of
       the connection.  Optional. Type uniline.

   CanonicalDomains
       When CanonicalizeHostname is enabled, this option specifies the list of domain suffixes in
       which to search for the specified destination host.  Optional. Type uniline.

   CanonicalizeFallbackLocal
       Specifies whether to fail with an error when hostname canonicalization fails.  The
       default, yes will attempt to look up the unqualified hostname using the system resolver's
       search rules. A value of no will cause ssh(1) to fail instantly if CanonicalizeHostname is
       enabled and the target hostname cannot be found in any of the domains specified by
       CanonicalDomains  Optional. Type boolean.

       upstream_default value :
           yes

   CanonicalizeHostname
       Controls whether explicit hostname canonicalization is performed. The default, no is not
       to perform any name rewriting and let the system resolver handle all hostname lookups. If
       set to yes then, for connections that do not use a ProxyCommand or ProxyJump ssh(1) will
       attempt to canonicalize the hostname specified on the command line using the
       CanonicalDomains suffixes and CanonicalizePermittedCNAMEs rules. If CanonicalizeHostname
       is set to always then canonicalization is applied to proxied connections too.

       If this option is enabled, then the configuration files are processed again using the new
       target name to pick up any new configuration in matching Host and Match stanzas. A value
       of none disables the use of a ProxyJump host.  Optional. Type enum. choice: 'always',
       'no', 'none', 'yes'.

       upstream_default value :
           no

   CanonicalizeMaxDots
       Specifies the maximum number of dot characters in a hostname before canonicalization is
       disabled. The default, 1, allows a single dot (i.e.  hostname.subdomain).  Optional. Type
       integer.

       upstream_default value :
           1

   CanonicalizePermittedCNAMEs
       Specifies rules to determine whether CNAMEs should be followed when

       canonicalizing hostnames. The rules consist of one or more arguments of source_domain_list
       :   target_domain_list where source_domain_list is a pattern-list of domains that may
       follow CNAMEs in canonicalization, and target_domain_list is a pattern-list of domains
       that they may resolve to.

       For example, Qq *.a.example.com:*.b.example.com,*.c.example.com will allow hostnames
       matching Qq *.a.example.com to be canonicalized to names in the Qq *.b.example.com or Qq
       *.c.example.com domains.

       A single argument of Qq none causes no CNAMEs to be considered for canonicalization. This
       is the default behaviour.  Optional. Type uniline.

   CASignatureAlgorithms
       Specifies which algorithms are allowed for signing of certificates by certificate
       authorities (CAs). The default is: ssh-ed25519, ecdsa-sha2-nistp256, ecdsa-sha2-nistp384,
       ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com,
       rsa-sha2-512, rsa-sha2-256

       If the specified list begins with a '+' character, then the specified algorithms will be
       appended to the default set instead of replacing them. If the specified list begins with a
       '-' character, then the specified algorithms (including wildcards) will be removed from
       the default set instead of replacing them.

       ssh(1) will not accept host certificates signed using algorithms other than those
       specified.  Optional. Type uniline.

   CertificateFile
       Specifies a file from which the user's certificate is read. A corresponding private key
       must be provided separately in order to use this certificate either from an IdentityFile
       directive or -i flag to ssh(1), via ssh-agent1, or via a PKCS11Provider or
       SecurityKeyProvider

       Arguments to CertificateFile may use the tilde syntax to refer to a user's home directory,
       the tokens described in the TOKENS section and environment variables as described in the
       ENVIRONMENT VARIABLES section.

       It is possible to have multiple certificate files specified in configuration files; these
       certificates will be tried in sequence. Multiple CertificateFile directives will add to
       the list of certificates used for authentication.  Optional. Type uniline.

   CheckHostIP
       If set to yes ssh(1) will additionally check the host IP address in the known_hosts file.
       This allows it to detect if a host key changed due to DNS spoofing and will add addresses
       of destination hosts to ~/.ssh/known_hosts in the process, regardless of the setting of
       StrictHostKeyChecking If the option is set to no (the default), the check will not be
       executed.  Optional. Type boolean.

       upstream_default value :
           no

   Ciphers
       Specifies the ciphers allowed and their order of preference. Multiple ciphers must be
       comma-separated. If the specified list begins with a '+' character, then the specified
       ciphers will be appended to the default set instead of replacing them. If the specified
       list begins with a '-' character, then the specified ciphers (including wildcards) will be
       removed from the default set instead of replacing them. If the specified list begins with
       a '^' character, then the specified ciphers will be placed at the head of the default set.

       The supported ciphers are: 3des-cbc aes128-cbc aes192-cbc aes256-cbc aes128-ctr aes192-ctr
       aes256-ctr aes128-gcm@openssh.comaes256-gcm@openssh.comchacha20-poly1305@openssh.com

       The default is: chacha20-poly1305@openssh.com, aes128-ctr, aes192-ctr, aes256-ctr,
       aes128-gcm@openssh.com, aes256-gcm@openssh.com

       The list of available ciphers may also be obtained using Qq 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).  The argument must be yes or no
       (the default).  Optional. Type boolean.

       upstream_default value :
           no

   Compression
       Specifies whether to use compression. The argument must be yes or no (the default).
       Optional. Type boolean.

       upstream_default value :
           no

   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. The
       default is 1.  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 timeout is applied both to establishing the
       connection and to performing the initial SSH protocol handshake and key exchange.
       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(1) to listen for control connections, but require
       confirmation using ssh-askpass1. If the ControlPath cannot be opened, ssh(1) will continue
       without connecting to a master instance.

       X11 and ssh-agent1 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 possible 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: 'ask', 'auto', 'autoask', 'no', 'yes'.

       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. Arguments to
       ControlPath may use the tilde syntax to refer to a user's home directory, the tokens
       described in the TOKENS section and environment variables as described in the ENVIRONMENT
       VARIABLES section.  It is recommended that any ControlPath used for opportunistic
       connection sharing include at least %h, %p, and %r (or alternatively %C) and be placed in
       a directory that is not writable by other users. This ensures that shared connections are
       uniquely identified.  Optional. Type uniline.

   ControlPersist
       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 (the default), 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 or 0, then the master connection will remain in the
       background indefinitely (until killed or closed via a mechanism such as the Qq ssh -O exit
       ) . If set to a time in seconds, or a time in any of the formats documented in
       sshd_config5, 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. 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.

   EnableEscapeCommandline
       Enables the command line option in the EscapeChar menu for interactive sessions (default
       '~C' ) . By default, the command line is disabled.  Optional. Type uniline.

   EnableSSHKeysign
       Setting this option to yes in the global client configuration file /etc/ssh/ssh_config
       enables the use of the helper program ssh-keysign8 during HostbasedAuthentication The
       argument must be yes or no (the default).  This option should be placed in the non-
       hostspecific section. See ssh-keysign8 for more information.  Optional. Type boolean.

       upstream_default value :
           no

   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.

   ExitOnForwardFailure
       Specifies whether ssh(1) should terminate the connection if it cannot set up all requested
       dynamic, tunnel, local, and remote port forwardings, (e.g. if either end is unable to bind
       and listen on a specified port). Note that ExitOnForwardFailure does not apply to
       connections made over port forwardings and will not, for example, cause ssh(1) to exit if
       TCP connections to the ultimate forwarding destination fail. The argument must be yes or
       no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   FingerprintHash
       Specifies the hash algorithm used when displaying key fingerprints. Valid options are: md5
       and sha256 (the default).  Optional. Type enum. choice: 'md5', 'sha256'.

       upstream_default value :
           sha256

   ForkAfterAuthentication
       Requests ssh to go to background just before command execution. This is useful if ssh is
       going to ask for passwords or passphrases, but the user wants it in the background. This
       implies the StdinNull configuration option being set to ''yes'' The recommended way to
       start X11 programs at a remote site is with something like ssh -f host xterm which is the
       same as ssh host xterm if the ForkAfterAuthentication configuration option is set to
       ''yes''

       If the ExitOnForwardFailure configuration option is set to ''yes'' then a client started
       with the ForkAfterAuthentication configuration option being set to ''yes'' will wait for
       all remote port forwards to be successfully established before placing itself in the
       background. The argument to this keyword must be yes (same as the -f option) or no (the
       default).  Optional. Type boolean.

       upstream_default value :
           no

   ForwardAgent
       Specifies whether the connection to the authentication agent (if any) will be forwarded to
       the remote machine. The argument may be yes no (the default), an explicit path to an agent
       socket or the name of an environment variable (beginning with '$' in which to find the
       path.

       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 :
           no

   ForwardX11
       Specifies whether X11 connections will be automatically redirected over the secure channel
       and DISPLAY set. The argument must be yes or no (the default).

       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 display 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 :
           no

   ForwardX11Timeout
       Specify a timeout for untrusted X11 forwarding using the format described in the TIME
       FORMATS section of sshd_config5. X11 connections received by ssh(1) after this time will
       be refused. Setting ForwardX11Timeout to zero will disable the timeout and permit X11
       forwarding for the life of the connection. The default is to disable untrusted X11
       forwarding after twenty minutes has elapsed.  Optional. Type integer.

   ForwardX11Trusted
       If this option is set to yes (the Debian-specific default), remote X11 clients will have
       full access to the original X11 display.

       If this option is set to no (the upstream default), 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.

   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. The argument must be yes or no (the default).  Optional.
       Type boolean.

       upstream_default value :
           no

   GlobalKnownHostsFile
       Specifies one or more files to use for the global host key database, separated by
       whitespace. The default is /etc/ssh/ssh_known_hosts /etc/ssh/ssh_known_hosts2.  Optional.
       Type uniline.

       default value :
           /etc/ssh/ssh_known_hosts /etc/ssh/ssh_known_hosts2

   GSSAPIAuthentication
       Specifies whether user authentication based on GSSAPI is allowed. The default is no
       Optional. Type boolean.

       upstream_default value :
           no

   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.

   GSSAPIDelegateCredentials
       Forward (delegate) credentials to the server. The default is no  Optional. Type boolean.

       upstream_default value :
           no

   GSSAPIKeyExchange
       Specifies whether key exchange based on GSSAPI may be used. When using GSSAPI key exchange
       the server need not have a host key. The default is ''no''  Optional. Type uniline.

   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 will delegate the renewed
       credentials to a session on the server.

       Checks are made to ensure that credentials are only propagated when the new credentials
       match the old ones on the originating client and where the receiving server still has the
       old set in its cache.

       The default is ''no''

       For this to work GSSAPIKeyExchange needs to be enabled in the server and also used by the
       client.  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.

   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. The default is ''no''  Optional. Type uniline.

   GSSAPIKexAlgorithms
       The list of key exchange algorithms that are offered for GSSAPI key exchange.  Possible
       values are gss-gex-sha1-, gss-group1-sha1-, gss-group14-sha1-, gss-group14-sha256-,

       gss-group16-sha512-, gss-nistp256-sha256-, gss-curve25519-sha256-
       The default is ''gss-group14-sha256-, gss-group16-sha512-, gss-nistp256-sha256-,
       gss-curve25519-sha256-, gss-gex-sha1-, gss-group14-sha1-'' This option only applies to
       connections using GSSAPI.  Optional. Type uniline.

   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 visually reveal identifying information if the file's contents are disclosed. The
       default is no Note that existing names and addresses in known hosts files will not be
       converted automatically, but may be manually hashed using ssh-keygen1. Use of this option
       may break facilities such as tab-completion that rely on being able to read unhashed host
       names from ~/.ssh/known_hosts.  Optional. Type boolean.

       upstream_default value :
           no

   HostbasedAcceptedAlgorithms
       Specifies the signature algorithms that will be used for hostbased authentication as a
       comma-separated list of patterns. Alternately if the specified list begins with a '+'
       character, then the specified signature algorithms will be appended to the default set
       instead of replacing them. If the specified list begins with a '-' character, then the
       specified signature algorithms (including wildcards) will be removed from the default set
       instead of replacing them. If the specified list begins with a '^' character, then the
       specified signature algorithms will be placed at the head of the default set.  The default
       for this option is: ssh-ed25519-cert-v01@openssh.com,
       ecdsa-sha2-nistp256-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com,
       ecdsa-sha2-nistp521-cert-v01@openssh.com, sk-ssh-ed25519-cert-v01@openssh.com,
       sk-ecdsa-sha2-nistp256-cert-v01@openssh.com, rsa-sha2-512-cert-v01@openssh.com,
       rsa-sha2-256-cert-v01@openssh.com, ssh-ed25519, ecdsa-sha2-nistp256, ecdsa-sha2-nistp384,
       ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com,
       rsa-sha2-512, rsa-sha2-256

       The -Q option of ssh(1) may be used to list supported signature algorithms. This was
       formerly named HostbasedKeyTypes.  Optional. Type uniline.

       Note: HostbasedAcceptedAlgorithms is migrated with '$old' and with:

       •   $old => "- HostbasedKeyTypes"

   HostbasedAuthentication
       Specifies whether to try rhosts based authentication with public key authentication. The
       argument must be yes or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   HostKeyAlgorithms
       Specifies the host key signature algorithms that the client wants to use in order of
       preference. Alternately if the specified list begins with a '+' character, then the
       specified signature algorithms will be appended to the default set instead of replacing
       them. If the specified list begins with a '-' character, then the specified signature
       algorithms (including wildcards) will be removed from the default set instead of replacing
       them. If the specified list begins with a '^' character, then the specified signature
       algorithms will be placed at the head of the default set. The default for this option is:
       ssh-ed25519-cert-v01@openssh.com, ecdsa-sha2-nistp256-cert-v01@openssh.com,
       ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com,
       sk-ssh-ed25519-cert-v01@openssh.com, sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
       rsa-sha2-512-cert-v01@openssh.com, rsa-sha2-256-cert-v01@openssh.com, ssh-ed25519,
       ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521,
       sk-ecdsa-sha2-nistp256@openssh.com, sk-ssh-ed25519@openssh.com, rsa-sha2-512, rsa-sha2-256

       If hostkeys are known for the destination host then this default is modified to prefer
       their algorithms.

       The list of available signature algorithms may also be obtained using Qq ssh -Q
       HostKeyAlgorithms .  Optional. Type uniline.

   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 and when validating host certificates.
       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. Arguments to Hostname accept the tokens described in the TOKENS
       section. Numeric IP addresses are also permitted (both on the command line and in Hostname
       specifications). The default is the name given on the command line.  Optional. Type
       uniline.

   IdentitiesOnly
       Specifies that ssh(1) should only use the configured authentication identity and
       certificate files (either the default files, or those explicitly configured in the
       ssh_config files or passed on the ssh(1) command-line), even if ssh-agent1 or a
       PKCS11Provider or SecurityKeyProvider offers more identities. The argument to this keyword
       must be yes or no (the default).  This option is intended for situations where ssh-agent
       offers many different identities.  Optional. Type boolean.

       upstream_default value :
           no

   IdentityAgent
       Specifies the UNIX socket used to communicate with the authentication agent.

       This option overrides the SSH_AUTH_SOCK environment variable and can be used to select a
       specific agent. Setting the socket name to none disables the use of an authentication
       agent. If the string Qq SSH_AUTH_SOCK is specified, the location of the socket will be
       read from the SSH_AUTH_SOCK environment variable. Otherwise if the specified value begins
       with a '$' character, then it will be treated as an environment variable containing the
       location of the socket.

       Arguments to IdentityAgent may use the tilde syntax to refer to a user's home directory,
       the tokens described in the TOKENS section and environment variables as described in the
       ENVIRONMENT VARIABLES section.  Optional. Type uniline.

   IdentityFile
       Specifies a file from which the user's DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
       authenticator-hosted Ed25519 or RSA authentication identity is read.  You can also specify
       a public key file to use the corresponding private key that is loaded in ssh-agent1 when
       the private key file is not present locally.  The default is ~/.ssh/id_rsa ~/.ssh/id_ecdsa
       ~/.ssh/id_ecdsa_sk ~/.ssh/id_ed25519 ~/.ssh/id_ed25519_sk and ~/.ssh/id_dsa Additionally,
       any identities represented by the authentication agent will be used for authentication
       unless IdentitiesOnly is set. If no certificates have been explicitly specified by
       CertificateFile ssh(1) will try to load certificate information from the filename obtained
       by appending -cert.pub to the path of a specified IdentityFile

       Arguments to IdentityFile may use the tilde syntax to refer to a user's home directory or
       the tokens described in the TOKENS section.

       It is possible to have multiple identity files specified in configuration files; all these
       identities will be tried in sequence. Multiple IdentityFile directives will add to the
       list of identities tried (this behaviour differs from that of other configuration
       directives).

       IdentityFile may be used in conjunction with IdentitiesOnly to select which identities in
       an agent are offered during authentication. IdentityFile may also be used in conjunction
       with CertificateFile in order to provide any certificate also needed for authentication
       with the identity.  Optional. Type list of 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.

   Include
       Include the specified configuration file(s). Multiple pathnames may be specified and each
       pathname may contain glob(7) wildcards and, for user configurations, shell-like '~'
       references to user home directories. Wildcards will be expanded and processed in lexical
       order. Files without absolute paths are assumed to be in ~/.ssh if included in a user
       configuration file or /etc/ssh if included from the system configuration file. Include
       directive may appear inside a Match or Host block to perform conditional inclusion.
       Optional. Type list of uniline.

   IPQoS
       Specifies the IPv4 type-of-service or DSCP class for connections. Accepted values are af11
       af12 af13 af21 af22 af23 af31 af32 af33 af41 af42 af43 cs0 cs1 cs2 cs3 cs4 cs5 cs6 cs7 ef
       le lowdelay throughput reliability a numeric value, or none to use the operating system
       default. 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 :
           af21 cs1

   KbdInteractiveAuthentication
       Specifies whether to use keyboard-interactive authentication. The argument to this keyword
       must be yes (the default) or no ChallengeResponseAuthentication is a deprecated alias for
       this.  Optional. Type boolean.

       upstream_default value :
           yes

   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 and pam  Optional. Type list of uniline.

   KexAlgorithms
       Specifies the available KEX (Key Exchange) algorithms. Multiple algorithms must be comma-
       separated. If the specified list begins with a '+' character, then the specified
       algorithms will be appended to the default set instead of replacing them. If the specified
       list begins with a '-' character, then the specified algorithms (including wildcards) will
       be removed from the default set instead of replacing them. If the specified list begins
       with a '^' character, then the specified algorithms will be placed at the head of the
       default set. The default is: sntrup761x25519-sha512@openssh.com, curve25519-sha256,
       curve25519-sha256@libssh.org, ecdh-sha2-nistp256, ecdh-sha2-nistp384, ecdh-sha2-nistp521,
       diffie-hellman-group-exchange-sha256, diffie-hellman-group16-sha512,
       diffie-hellman-group18-sha512, diffie-hellman-group14-sha256

       The list of available key exchange algorithms may also be obtained using Qq ssh -Q kex .
       Optional. Type uniline.

   KnownHostsCommand
       Specifies a command to use to obtain a list of host keys, in addition to those listed in
       UserKnownHostsFile and GlobalKnownHostsFile This command is executed after the files have
       been read. It may write host key lines to standard output in identical format to the usual
       files (described in the VERIFYING HOST KEYS section in ssh(1)). Arguments to
       KnownHostsCommand accept the tokens described in the TOKENS section. The command may be
       invoked multiple times per connection: once when preparing the preference list of host key
       algorithms to use, again to obtain the host key for the requested host name and, if
       CheckHostIP is enabled, one more time to obtain the host key matching the server's
       address. If the command exits abnormally or returns a non-zero exit status then the
       connection is terminated.  Optional. Type uniline.

   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. Arguments to LocalCommand accept the tokens described in the TOKENS section.

       The command is run synchronously and does not have access to the session of the ssh(1)
       that spawned it. It should not be used for interactive commands.

       This directive is ignored unless PermitLocalCommand has been enabled.  Optional. Type
       uniline.

   LocalForward
       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 specifies the listener
       and may be [bind_address : port ] or a Unix domain socket path. The second argument is the
       destination and may be host :   hostport or a Unix domain socket path if the remote host
       supports it.

       IPv6 addresses can be specified by enclosing addresses in square brackets.  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. Unix domain socket paths may use
       the tokens described in the TOKENS section and environment variables as described in the
       ENVIRONMENT VARIABLES section.  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: 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: 'DEBUG', 'DEBUG1', 'DEBUG2',
       'DEBUG3', 'ERROR', 'FATAL', 'INFO', 'QUIET', 'VERBOSE'.

       upstream_default value :
           INFO

   LogVerbose
       Specify one or more overrides to LogLevel. An override consists of a pattern lists that
       matches the source file, function and line number to force detailed logging for. For
       example, an override pattern of: kex.c:*:1000,*:kex_exchange_identification():*,
       packet.c:*

       would enable detailed logging for line 1000 of kex.c everything in the Fn
       kex_exchange_identification function, and all code in the packet.c file. This option is
       intended for debugging and no overrides are enabled by default.  Optional. Type uniline.

   MACs
       Specifies the MAC (message authentication code) algorithms

       in order of preference. The MAC algorithm is used for data integrity protection. Multiple
       algorithms must be comma-separated. If the specified list begins with a '+' character,
       then the specified algorithms will be appended to the default set instead of replacing
       them. If the specified list begins with a '-' character, then the specified algorithms
       (including wildcards) will be removed from the default set instead of replacing them. If
       the specified list begins with a '^' character, then the specified algorithms will be
       placed at the head of the default set.

       The algorithms that contain Qq -etm calculate the MAC after encryption (encrypt-then-mac).
       These are considered safer and their use recommended.

       The default is: umac-64-etm@openssh.com, umac-128-etm@openssh.com,
       hmac-sha2-256-etm@openssh.com, hmac-sha2-512-etm@openssh.com, hmac-sha1-etm@openssh.com,
       umac-64@openssh.com, umac-128@openssh.com, hmac-sha2-256, hmac-sha2-512, hmac-sha1

       The list of available MAC algorithms may also be obtained using Qq ssh -Q mac .  Optional.
       Type uniline.

   NoHostAuthenticationForLocalhost
       Disable host authentication for localhost (loopback addresses). The argument to this
       keyword must be yes or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   NumberOfPasswordPrompts
       Specifies the number of password prompts before giving up. The argument to this keyword
       must be an integer. The default is 3.  Optional. Type integer.

       upstream_default value :
           3

   PasswordAuthentication
       Specifies whether to use password authentication. The argument to this keyword must be yes
       (the default) or no  Optional. Type boolean.

       upstream_default value :
           yes

   PermitLocalCommand
       Allow local command execution via the LocalCommand option or using the !  command escape
       sequence in ssh(1). The argument must be yes or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   PermitRemoteOpen
       Specifies the destinations to which remote TCP port forwarding is permitted when
       RemoteForward is used as a SOCKS proxy. The forwarding specification must be one of the
       following forms:

       PermitRemoteOpen host : port PermitRemoteOpen IPv4_addr : port PermitRemoteOpen [
       IPv6_addr ] : port

       Multiple forwards may be specified by separating them with whitespace. An argument of any
       can be used to remove all restrictions and permit any forwarding requests. An argument of
       none can be used to prohibit all forwarding requests. The wildcard '*' can be used for
       host or port to allow all hosts or ports respectively. Otherwise, no pattern matching or
       address lookups are performed on supplied names.  Optional. Type list of uniline.

   PKCS11Provider
       Specifies which PKCS#11 provider to use or none to indicate that no provider should be
       used (the default). The argument to this keyword is a path to the PKCS#11 shared library
       ssh(1) should use to communicate with a PKCS#11 token providing keys for user
       authentication.  Optional. Type uniline.

   Port
       Specifies the port number to connect on the remote host. The default is 22.  Optional.
       Type uniline.

   PreferredAuthentications
       Specifies the order in which the client should try authentication methods. This allows a
       client to prefer one method (e.g. keyboard-interactive over another method (e.g. password
       ) The default is: gssapi-with-mic, hostbased, publickey, keyboard-interactive, password.
       Optional. Type list of uniline.

   ProxyCommand
       Specifies the command to use to connect to the server. The command string extends to the
       end of the line, and is executed using the user's shell 'exec' directive to avoid a
       lingering shell process.

       Arguments to ProxyCommand accept the tokens described in the TOKENS section. The command
       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.  Optional. Type uniline.

   ProxyJump
       Specifies one or more jump proxies as either [user  @ ] host [: port ] or an ssh URI .
       Multiple proxies may be separated by comma characters and will be visited sequentially.
       Setting this option will cause ssh(1) to connect to the target host by first making a
       ssh(1) connection to the specified ProxyJump host and then establishing a TCP forwarding
       to the ultimate target from there. Setting the host to none disables this option entirely.

       Note that this option will compete with the ProxyCommand option - whichever is specified
       first will prevent later instances of the other from taking effect.

       Note also that the configuration for the destination host (either supplied via the
       command-line or the configuration file) is not generally applied to jump hosts.
       ~/.ssh/config should be used if specific configuration is required for jump hosts.
       Optional. Type list of uniline.

   ProxyUseFdpass
       Specifies that ProxyCommand will pass a connected file descriptor back to ssh(1) instead
       of continuing to execute and pass data. The default is no  Optional. Type boolean.

       upstream_default value :
           no

   PubkeyAcceptedAlgorithms
       Specifies the signature algorithms that will be used for public key authentication as a
       comma-separated list of patterns. If the specified list begins with a '+' character, then
       the algorithms after it will be appended to the default instead of replacing it. If the
       specified list begins with a '-' character, then the specified algorithms (including
       wildcards) will be removed from the default set instead of replacing them. If the
       specified list begins with a '^' character, then the specified algorithms will be placed
       at the head of the default set. The default for this option is:
       ssh-ed25519-cert-v01@openssh.com, ecdsa-sha2-nistp256-cert-v01@openssh.com,
       ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com,
       sk-ssh-ed25519-cert-v01@openssh.com, sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
       rsa-sha2-512-cert-v01@openssh.com, rsa-sha2-256-cert-v01@openssh.com, ssh-ed25519,
       ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com,
       sk-ecdsa-sha2-nistp256@openssh.com, rsa-sha2-512, rsa-sha2-256

       The list of available signature algorithms may also be obtained using Qq ssh -Q
       PubkeyAcceptedAlgorithms .  Optional. Type uniline.

       Note: PubkeyAcceptedAlgorithms is migrated with '$old' and with:

       •   $old => "- PubkeyAcceptedKeyTypes"

   PubkeyAuthentication
       Specifies whether to try public key authentication. The argument to this keyword must be
       yes (the default), no unbound or host-bound The final two options enable public key
       authentication while respectively disabling or enabling the OpenSSH host-bound
       authentication protocol extension required for restricted ssh-agent1 forwarding.
       Optional. Type enum. choice: 'host-bound', 'no', 'unbound', 'yes'.

       upstream_default value :
           yes

   RekeyLimit
       Specifies the maximum amount of data that may be transmitted or received before the
       session key is renegotiated, optionally followed by a maximum amount of time that may pass
       before the session key is renegotiated. The first argument is specified in bytes and may
       have a suffix of 'K' 'M' or 'G' to indicate Kilobytes, Megabytes, or Gigabytes,
       respectively. The default is between '1G' and '4G' depending on the cipher. The optional
       second value is specified in seconds and may use any of the units documented in the TIME
       FORMATS section of sshd_config5. The default value for RekeyLimit is default none which
       means that rekeying is performed after the cipher's default amount of data has been sent
       or received and no time based rekeying is done.  Optional. Type uniline.

   RemoteCommand
       Specifies a command to execute on the remote 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. Arguments to RemoteCommand accept the tokens described in the TOKENS section.
       Optional. Type uniline.

   RemoteForward
       Specifies that a TCP port on the remote machine be forwarded over the secure channel. The
       remote port may either be forwarded to a specified host and port from the local machine,
       or may act as a SOCKS 4/5 proxy that allows a remote client to connect to arbitrary
       destinations from the local machine. The first argument is the listening specification and
       may be [bind_address : port ] or, if the remote host supports it, a Unix domain socket
       path. If forwarding to a specific destination then the second argument must be host :
       hostport or a Unix domain socket path, otherwise if no destination argument is specified
       then the remote forwarding will be established as a SOCKS proxy.  When acting as a SOCKS
       proxy, the destination of the connection can be restricted by PermitRemoteOpen

       IPv6 addresses can be specified by enclosing addresses in square brackets.  Multiple
       forwardings may be specified, and additional forwardings can be given on the command line.
       Privileged ports can be forwarded only when logging in as root on the remote machine. Unix
       domain socket paths may use the tokens described in the TOKENS section and environment
       variables as described in the ENVIRONMENT VARIABLES section.

       If the port argument is 0, the listen port will be dynamically allocated on the server and
       reported to the client at run time.

       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 interfaces. Specifying a remote bind_address will only succeed if the server's
       GatewayPorts option is enabled (see sshd_config5).  Optional. Type list of node of class
       Ssh::PortForward .

   RequestTTY
       Specifies whether to request a pseudo-tty for the session. The argument may be one of: no
       (never request a TTY), yes (always request a TTY when standard input is a TTY), force
       (always request a TTY) or auto (request a TTY when opening a login session). This option
       mirrors the -t and -T flags for ssh(1).  Optional. Type enum. choice: 'auto', 'force',
       'no', 'yes'.

   RequiredRSASize
       Specifies the minimum RSA key size (in bits) that ssh(1) will accept. User authentication
       keys smaller than this limit will be ignored. Servers that present host keys smaller than
       this limit will cause the connection to be terminated. The default is 1024 bits. Note that
       this limit may only be raised from the default.  Optional. Type integer.

       upstream_default value :
           1024

   RevokedHostKeys
       Specifies revoked host public keys. Keys listed in this file will be refused for host
       authentication. Note that if this file does not exist or is not readable, then host
       authentication will be refused for all hosts. Keys may be specified as a text file,
       listing one public key per line, or as an OpenSSH Key Revocation List (KRL) as generated
       by ssh-keygen1. For more information on KRLs, see the KEY REVOCATION LISTS section in
       ssh-keygen1. Arguments to RevokedHostKeys may use the tilde syntax to refer to a user's
       home directory, the tokens described in the TOKENS section and environment variables as
       described in the ENVIRONMENT VARIABLES section.  Optional. Type uniline.

   SecurityKeyProvider
       Specifies a path to a library that will be used when loading any FIDO authenticator-hosted
       keys, overriding the default of using the built-in USB HID support.

       If the specified value begins with a '$' character, then it will be treated as an
       environment variable containing the path to the library.  Optional. Type uniline.

   SendEnv
       Specifies what variables from the local environ(7) should be sent to the server. The
       server must also support it, and the server must be configured to accept these environment
       variables. Note that the TERM environment variable is always sent whenever a pseudo-
       terminal is requested as it is required by the protocol. Refer to AcceptEnv in
       sshd_config5 for how to configure the server. Variables are specified by name, which may
       contain wildcard characters.  Multiple environment variables may be separated by
       whitespace or spread across multiple SendEnv directives.

       See PATTERNS for more information on patterns.

       It is possible to clear previously set SendEnv variable names by prefixing patterns with -
       The default is not to send any environment variables.  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 (below). The server alive messages are sent through the encrypted
       channel and therefore 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 connection has become unresponsive.

       The default value is 3. If, for example, ServerAliveInterval (see below) is set to 15 and
       ServerAliveCountMax is left at the default, if the server becomes unresponsive, ssh will
       disconnect after approximately 45 seconds.  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 (Debian-specific). ProtocolKeepAlives and
       SetupTimeOut are Debian-specific compatibility aliases for this option.  Optional. Type
       integer.

       upstream_default value :
           0

   SessionType
       May be used to either request invocation of a subsystem on the remote system, or to
       prevent the execution of a remote command at all. The latter is useful for just forwarding
       ports. The argument to this keyword must be none (same as the -N option), subsystem (same
       as the -s option) or default (shell or command execution).  Optional. Type enum. choice:
       'default', 'none', 'subsystem'.

   SetEnv
       Directly specify one or more environment variables and their contents to be sent to the
       server. Similarly to SendEnv with the exception of the TERM variable, the server must be
       prepared to accept the environment variable.  Optional. Type uniline.

   StdinNull
       Redirects stdin from /dev/null (actually, prevents reading from stdin). Either this or the
       equivalent -n option must be used when ssh is run in the background. The argument to this
       keyword must be yes (same as the -n option) or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   StreamLocalBindMask
       Sets the octal file creation mode mask (umask) used when creating a Unix-domain socket
       file for local or remote port forwarding. This option is only used for port forwarding to
       a Unix-domain socket file.

       The default value is 0177, which creates a Unix-domain socket file that is readable and
       writable only by the owner. Note that not all operating systems honor the file mode on
       Unix-domain socket files.  Optional. Type uniline.

   StreamLocalBindUnlink
       Specifies whether to remove an existing Unix-domain socket file for local or remote port
       forwarding before creating a new one. If the socket file already exists and
       StreamLocalBindUnlink is not enabled, ssh will be unable to forward the port to the Unix-
       domain socket file. This option is only used for port forwarding to a Unix-domain socket
       file.

       The argument must be yes or no (the default).  Optional. Type boolean.

       upstream_default value :
           no

   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 man-in-the-middle (MITM) 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 accept-new then ssh will automatically add new host keys to the
       user's known_hosts file, but will not permit connections to hosts with changed host keys.
       If this flag is set to no or off ssh will automatically add new host keys to the user
       known hosts files and allow connections to hosts with changed hostkeys to proceed, subject
       to some restrictions. If this flag is set to ask (the default), 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.  Optional. Type
       enum. choice: 'yes', 'accept-new', 'no', 'off', 'ask'.

       upstream_default value :
           ask

   SyslogFacility
       Gives the facility code that is used when logging messages from ssh(1). The possible
       values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6,
       LOCAL7. The default is USER.  Optional. Type enum. choice: 'AUTH', 'DAEMON', 'LOCAL0',
       'LOCAL1', 'LOCAL2', 'LOCAL3', 'LOCAL4', 'LOCAL5', 'LOCAL6', 'LOCAL7', 'USER'.

       upstream_default value :
           USER

   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 See also
       ServerAliveInterval for protocol-level keepalives.  Optional. Type boolean.

       upstream_default value :
           yes

   Tag
       Specify a configuration tag name that may be later used by a Match directive to select a
       block of configuration.  Optional. Type uniline.

   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 (the default). Specifying yes
       requests the default tunnel mode, which is point-to-point  Optional. Type enum. choice:
       'ethernet', 'no', 'point-to-point', 'yes'.

       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  Optional. Type uniline.

       upstream_default value :
           any:any

   UpdateHostKeys
       Specifies whether ssh(1) should accept notifications of additional hostkeys from the
       server sent after authentication has completed and add them to UserKnownHostsFile The
       argument must be yes no or ask This option allows learning alternate hostkeys for a server
       and supports graceful key rotation by allowing a server to send replacement public keys
       before old ones are removed.

       Additional hostkeys are only accepted if the key used to authenticate the host was already
       trusted or explicitly accepted by the user, the host was authenticated via
       UserKnownHostsFile (i.e. not GlobalKnownHostsFile and the host was authenticated using a
       plain key and not a certificate.

       UpdateHostKeys is enabled by default if the user has not overridden the default
       UserKnownHostsFile setting and has not enabled VerifyHostKeyDNS otherwise UpdateHostKeys
       will be set to no

       If UpdateHostKeys is set to ask then the user is asked to confirm the modifications to the
       known_hosts file. Confirmation is currently incompatible with ControlPersist and will be
       disabled if it is enabled.

       Presently, only sshd(8) from OpenSSH 6.8 and greater support the Qq hostkeys@openssh.com
       protocol extension used to inform the client of all the server's hostkeys.  Optional. Type
       enum. choice: 'ask', 'no', 'yes'.

   User
       Specifies the user to log in as. This can be useful when a different 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 one or more files to use for the user host key database, separated by
       whitespace. Each filename may use tilde notation to refer to the user's home directory,
       the tokens described in the TOKENS section and environment variables as described in the
       ENVIRONMENT VARIABLES section. A value of none causes ssh(1) to ignore any user-specific
       known hosts files. The default is ~/.ssh/known_hosts ~/.ssh/known_hosts2.  Optional. Type
       list of 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
       default is no

       See also VERIFYING HOST KEYS in ssh(1).  Optional. Type enum. choice: 'ask', 'no', 'yes'.

       upstream_default value :
           no

   VisualHostKey
       If this flag is set to yes an ASCII art representation of the remote host key fingerprint
       is printed in addition to the fingerprint string at login and for unknown host keys. If
       this flag is set to no (the default), no fingerprint strings are printed at login and only
       the fingerprint string will be printed for unknown host keys.  Optional. Type uniline.

       upstream_default value :
           no

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

       upstream_default value :
           /usr/bin/xauth

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

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

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

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

   Match
       Restricts the following declarations (up to the next Host or Match keyword) to be used
       only when the conditions following the Match keyword are satisfied. Match conditions are
       specified using one or more criteria or the single token all which always matches. The
       available criteria keywords are: canonical final exec localnetwork host originalhost Tag
       user and localuser The all criteria must appear alone or immediately after canonical or
       final Other criteria may be combined arbitrarily. All criteria but all canonical and final
       require an argument. Criteria may be negated by prepending an exclamation mark ('!' )

       The canonical keyword matches only when the configuration file is being re-parsed after
       hostname canonicalization (see the CanonicalizeHostname option). This may be useful to
       specify conditions that work with canonical host names only.

       The final keyword requests that the configuration be re-parsed (regardless of whether
       CanonicalizeHostname is enabled), and matches only during this final pass. If
       CanonicalizeHostname is enabled, then canonical and final match during the same pass.

       The exec keyword executes the specified command under the user's shell. If the command
       returns a zero exit status then the condition is considered true.  Commands containing
       whitespace characters must be quoted. Arguments to exec accept the tokens described in the
       TOKENS section.

       The localnetwork keyword matches the addresses of active local network interfaces against
       the supplied list of networks in CIDR format. This may be convenient for varying the
       effective configuration on devices that roam between networks. Note that network address
       is not a trustworthy criteria in many situations (e.g. when the network is automatically
       configured using DHCP) and so caution should be applied if using it to control security-
       sensitive configuration.

       The other keywords' criteria must be single entries or comma-separated lists and may use
       the wildcard and negation operators described in the PATTERNS section. The criteria for
       the host keyword are matched against the target hostname, after any substitution by the
       Hostname or CanonicalizeHostname options. The originalhost keyword matches against the
       hostname as it was specified on the command-line. The tagged keyword matches a tag name
       specified by a prior Tag directive or on the ssh(1) command-line using the -P flag. The
       user keyword matches against the target username on the remote host. The localuser keyword
       matches against the name of the local user running ssh(1) (this keyword may be useful in
       system-wide ssh_config files).  Optional. Type hash of node of class Ssh::HostElement .

SEE ALSO

       •   cme

       •   Config::Model::models::Ssh::HostElement

       •   Config::Model::models::Ssh::PortForward

LICENSE

       LGPL2