SSH Configuration Mode Commands

SSH Configuration Mode Commands
 
The Secure Shell Configuration Mode is used to manage the SSH server options for the current context.
note_smallImportant: You must use the ssh generate key command in Context Configuration Mode to generate the sshd keys before you can configure the sshd server
authorized-key
Sets or removes a user name having authorized keys for access to the sshd server in the current context.
Product
All
Privilege
Security Administrator, Administrator
Syntax
authorized-key username user_name host host _name [ type { v2-dsa | v2-rsa } ]
default
Resets the parameter to the default value.
username
Sets a username as having authorized keys for access to the sshd server.
user_name
Specifies the username entered as an alphanumeric string of 1 through 255 characters.
host
Associates an SSH host having the authorization keys for the username.
host_name
Specifies the host name entered as an alphanumeric string of 1 through 255 characters.
[ type { v2-dsa | v2-rsa } ]
Specifies which type of SSH authorization key will be accepted instead of all key types. The options are: v2-dsa (SSHv2 Digital Signature Algorithm), or v2-rsa (SSHv2 Rivest, Shamir and Adleman).
Usage
Use this command to set a username with authorized keys for access to the sshd server within the current context.
Example
The following command specifies that username dbailey with authorization keys at sshserver can access the system with all types of authorization keys:
authorized-key username dbailey host sshserver
end
Exits the current configuration mode and returns to the Exec mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
end
Usage
Use this command to return to the Exec mode.
exit
Exits the current mode and returns to the parent configuration mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
exit
Usage
Use this command to return to the parent configuration mode.
listen
Configures the SSH server in the current context to only listen for connections from the interface with the specified IP address. The default behavior is to listen on all interfaces.
Product
All
Privilege
Security Administrator, Administrator
Syntax
listen ip_address
no listen
no
Disable listening for a specific interface address and enable listening on all interfaces.
ip_address
Enables listening only on the interface with the specified IP address. ip_address must be entered using IPv4 dotted-decimal notation.
Usage
Use this command to configure the SSH server for the current context to only listen for connections from the interface with the specified IP address. Only one IP address may be set for listening.
Example
The following command specifies that the Server should only listen for connections in the interface with the IP address of 192.168.0.10:
listen 192.168.0.10
max servers
Configures the maximum number of SSH servers that can be started within any 60-second interval. If this limit is reached, the system waits two minutes before trying to start any more servers.
Product
All
Privilege
Security Administrator, Administrator
Syntax
max servers number
number
Default: 40
Specifies the maximum number of servers that can be spawned in any 60-second interval. number must be an integer from 1 through 100.
Usage
Set the number of servers to tune the system response as a heavily loaded system may need more servers to support the incoming requests.
The converse would be true as well in that a system can benefit by reducing the number of servers such that telnet services do not cause excessive system impact to other services.
Example
max servers 50
subsystem
Configures the system to perform file transfers using secure FTP (SFTP) over ssh v2. Administrator users must be configured with the FTP attribute privilege to issue this command.
Product
All
Privilege
Security Administrator, Administrator
Syntax
[ no ] subsystem { cli | sftp }
no
Disables either the SFTP ssh file transfer method or disables access to the CLI via ssh.
cli
Default: Enabled
Configures the SSH system for the current context to allow access to the CLI.
sftp
Default: Disabled
Enables the SSH system for the current context to perform file transfers using secure FTP (SFTP) over ssh v2.
Usage
Use this command to enable or disable file transfers using secure ftp over an ssh v2 tunnel.
Also use this command to enable or disable access to the CLI over an SSH connection.
Example
The following command enables SFTP for the current context:
subsystem sftp
The following command disables access to the CLI through an SSH session for the current context:
no subsystem cli
 
 
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