Login Control Commands

login-control

Syntax

login-control

Context

config>system

Description

This command enables the context to configure the session control for console, FTP, SSH, and Telnet sessions.

exponential-backoff

Syntax

[no] exponential-backoff

Context

config>system>login-control

Description

This command enables the exponential backoff of the login prompt. The exponential-backoff command is used to deter dictionary attacks, when a malicious user can gain access to the CLI by using a script to try admin with any conceivable password.

The no form of the command disables exponential-backoff.

Default

no exponential-backoff

ftp

Syntax

ftp

Context

config>system>login-control

Description

This command enables the context to configure FTP login control parameters.

inbound-max-sessions

Syntax

inbound-max-sessions value

no inbound-max-sessions

Context

config>system>login-control>ftp

Description

This command configures the maximum number of concurrent inbound FTP sessions.

This value is the combined total of inbound and outbound sessions.

The no form of the command reverts to the default value.

Default

3

Parameters

value

the maximum number of concurrent FTP sessions on the node

Values

0 to 5

idle-timeout

Syntax

idle-timeout {minutes | disable}

no idle-timeout

Context

config>system>login-control

Description

This command configures the idle timeout for FTP, console, SSH, and Telnet sessions before the session is terminated by the system.

By default, each idle FTP, console, SSH, or Telnet session times out after 30 minutes of inactivity.

The no form of the command reverts to the default value.

Default

30

Parameters

minutes

the idle timeout in minutes

Values

1 to 1440

disable

when the disable option is specified, a session will never time out. To re-enable idle timeout, enter the command without the disable option.

login-banner

Syntax

[no] login-banner

Context

config>system>login-control

Description

This command enables or disables the display of a login banner. The login banner contains the 7705 SAR copyright and build date information for a console login attempt.

The no form of the command causes only the configured pre-login-message and a generic login prompt to display.

motd

Syntax

motd {url url-prefix:source-url | text motd-text-string}

no motd

Context

config>system>login-control

Description

This command creates the message of the day that is displayed after a successful console login. Only one message can be configured.

The no form of the command removes the message.

Default

no motd

Parameters

url-prefix: source-url

when the message of the day is present as a text file, provide both the url-prefix and the source-url of the file containing the message of the day. The URL prefix can be local or remote.

motd-text-string

the text of the message of the day, up to 900 characters long. The motd-text-string must be enclosed in double quotes. Multiple text strings are not appended to one another.

Some special characters can be used to format the message text. The ‟\n” character creates multi-line MOTDs and the ‟\r” character restarts at the beginning of the new line. For example, entering ‟\n\r” will start the string at the beginning of the new line, while entering ‟\n” will start the second line below the last character from the first line.

pre-login-message

Syntax

pre-login-message login-text-string [name]

no pre-login-message

Context

config>system>login-control

Description

This command creates a message displayed prior to console login attempts on the console via Telnet.

Only one message can be configured. If multiple pre-login messages are configured, the last message entered overwrites the previous entry.

The system name can be added to an existing message without affecting the current pre-login message.

The no form of the command removes the message.

Default

no pre-login-message

Parameters

login-text-string

a text string, up to 900 characters. Any printable, 7-bit ASCII characters can be used. If the string contains special characters (such as #, $, or spaces), the entire string must be enclosed within double quotes.

name

when the keyword name is defined, the configured system name is always displayed first in the login message. To remove the name from the login message, the message must be cleared and a new message entered without the name.

ssh

Syntax

ssh

Context

config>system>login-control

Description

This command enables the context to configure SSH login control parameters.

disable-graceful-shutdown

Syntax

[no] disable-graceful-shutdown

Context

config>system>login-control>ssh

Description

This command disables graceful shutdown of SSH sessions.

By default, SSH always performs a graceful shutdown on a TCP connection. When graceful shutdown is disabled, SSH sends a FIN message and then immediately terminates the connection.

The no form of the command enables graceful shutdown of SSH sessions.

Default

no disable-graceful-shutdown

inbound-max-sessions

Syntax

inbound-max-sessions value

no inbound-max-sessions

Context

config>system>login-control>ssh

Description

This command limits the number of inbound SSH sessions. Each 7705 SAR router is limited to a total of 15 inbound SSH sessions (IPv4 and IPv6).

The no form of the command reverts to the default value.

Default

5

Parameters

value

the maximum number of concurrent inbound SSH sessions, expressed as an integer

Values

0 to 15

outbound-max-sessions

Syntax

outbound-max-sessions value

no outbound-max-sessions

Context

config>system>login-control>ssh

Description

This command limits the number of outbound SSH sessions. Each 7705 SAR router is limited to a total of 15 outbound SSH sessions (IPv4 and IPv6).

The no form of the command reverts to the default value.

Default

5

Parameters

value

the maximum number of concurrent outbound SSH sessions, expressed as an integer

Values

0 to 15

telnet

Syntax

telnet

Context

config>system>login-control

Description

This command enables the context to configure the Telnet login control parameters.

enable-graceful-shutdown

Syntax

[no] enable-graceful-shutdown

Context

config>system>login-control>telnet

Description

This command enables graceful shutdown of Telnet sessions.

When graceful shutdown is enabled, Telnet sends a FIN message and waits for an acknowledgment before terminating the TCP connection.

The no form of the command disables graceful shutdown of Telnet sessions.

Default

no enable-graceful-shutdown

inbound-max-sessions

Syntax

inbound-max-sessions value

no inbound-max-sessions

Context

config>system>login-control>telnet

Description

This command limits the number of inbound Telnet sessions. Each 7705 SAR router is limited to a total of 15 inbound Telnet sessions (IPv4 and IPv6).

The no form of the command reverts to the default value.

Default

5

Parameters

value

the maximum number of concurrent inbound Telnet sessions, expressed as an integer

Values

0 to 15

outbound-max-sessions

Syntax

outbound-max-sessions value

no outbound-max-sessions

Context

config>system>login-control>telnet

Description

This command limits the number of outbound Telnet sessions. Each 7705 SAR router is limited to a total of 15 outbound Telnet sessions (IPv4 and IPv6).

The no form of the command reverts to the default value.

Default

5

Parameters

value

the maximum number of concurrent outbound Telnet sessions, expressed as an integer

Values

0 to 15

ttl-security

Syntax

ttl-security min-ttl-value

no ttl-security

Context

config>system>login-control>telnet

config>system>login-control>ssh

Description

This command configures TTL security parameters for incoming packets. When the feature is enabled, SSH or Telnet connections will accept incoming IP packets from a peer only if the TTL value in the packet is greater than or equal to the minimum TTL value configured for that peer.

The no form of the command disables TTL security.

Default

no ttl-security

Parameters

min-ttl-value

specifies the minimum TTL value for an incoming packet

Values

1 to 255