Cisco Nexus 6000 Series NX-OS Security Command Reference
T Commands
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T Commands

Table Of Contents

T Commands

tacacs-server deadtime

tacacs-server directed-request

tacacs-server host

tacacs-server key

tacacs-server timeout

telnet

telnet server enable

telnet6


T Commands


This chapter describes the Cisco NX-OS security commands that begin with T.

tacacs-server deadtime

To set a periodic time interval where a nonreachable (nonresponsive) TACACS+ server is monitored for responsiveness, use the tacacs-server deadtime command. To disable the monitoring of the nonresponsive TACACS+ server, use the no form of this command.

tacacs-server deadtime minutes

no tacacs-server deadtime minutes

Syntax Description

time

Time interval in minutes. The range is from 1 to 1440.


Command Default

0 minutes

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

Setting the time interval to zero disables the timer. If the dead-time interval for an individual TACACS+ server is greater than zero (0), that value takes precedence over the value set for the server group.

When the dead-time interval is 0 minutes, TACACS+ server monitoring is not performed unless the TACACS+ server is part of a server group and the dead-time interval for the group is greater than 0 minutes.

You must use the feature tacacs+ command before you configure TACACS+.

Examples

This example shows how to configure the dead-time interval and enable periodic monitoring:

switch(config)# tacacs-server deadtime 10 
 
   

This example shows how to revert to the default dead-time interval and disable periodic monitoring:

switch(config)# no tacacs-server deadtime 10 
 
   

Related Commands

Command
Description

deadtime

Sets a dead-time interval for monitoring a nonresponsive RADIUS or TACACS+ server group.

feature tacacs+

Enables TACACS+.

show tacacs-server

Displays TACACS+ server information.


tacacs-server directed-request

To allow users to send authentication requests to a specific TACACS+ server when logging in, use the tacacs-server directed request command. To revert to the default, use the no form of this command.

tacacs-server directed-request

no tacacs-server directed-request

Syntax Description

This command has no arguments or keywords.

Command Default

Sends the authentication request to the configured TACACS+ server groups.

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

You must use the feature tacacs+ command before you configure TACACS+.

During login, the user can specify the username@vrfname:hostname, where vrfname is the VRF to use and hostname is the name of a configured TACACS+ server. The username is sent to the server name for authentication.

Examples

This example shows how to allow users to send authentication requests to a specific TACACS+ server when logging in:

switch(config)# tacacs-server directed-request 
 
   

This example shows how to disallow users to send authentication requests to a specific TACACS+ server when logging in:

switch(config)# no tacacs-server directed-request 
 
   

Related Commands

Command
Description

feature tacacs+

Enables TACACS+.

show tacacs-server directed request

Displays a directed request TACACS+ server configuration.


tacacs-server host

To configure TACACS+ server host parameters, use the tacacs-server host command. To revert to the defaults, use the no form of this command.

tacacs-server host {hostname | ipv4-address | ipv6-address} [key [0 | 7] shared-secret] [port port-number] [test {idle-time time | password password | username name}] [timeout seconds]

no tacacs-server host {hostname | ipv4-address | ipv6-address} [key [0 | 7] shared-secret] [port port-number] [test {idle-time time | password password | username name}] [timeout seconds]

Syntax Description

hostname

TACACS+ server Domain Name Server (DNS) name. The name is alphanumeric, case sensitive, and has a maximum of 256 characters.

ipv4-address

TACACS+ server IPv4 address in the A.B.C.D format.

ipv6-address

TACACS+ server IPv6 address in the X:X:X::X format.

key

(Optional) Configures the TACACS+ server's shared secret key.

0

(Optional) Configures a preshared key specified in clear text (indicated by 0) to authenticate communication between the TACACS+ client and server. This is the default.

7

(Optional) Configures a preshared key specified in encrypted text (indicated by 7) to authenticate communication between the TACACS+ client and server.

shared-secret

Preshared key to authenticate communication between the TACACS+ client and server. The preshared key is alphanumeric, case sensitive, and has a maximum of 63 characters.

port port-number

(Optional) Configures a TACACS+ server port for authentication. The range is from 1 to 65535.

test

(Optional) Configures parameters to send test packets to the TACACS+ server.

idle-time time

(Optional) Specifies the time interval (in minutes) for monitoring the server. The time range is 1 to 1440 minutes.

password password

(Optional) Specifies a user password in the test packets. The password is alphanumeric, case sensitive, and has a maximum of 32 characters.

username name

(Optional) Specifies a user name in the test packets. The username is alphanumeric, case sensitive, and has a maximum of 32 characters.

timeout seconds

(Optional) Configures a TACACS+ server timeout period (in seconds) between retransmissions to the TACACS+ server. The range is from 1 to 60 seconds.


Command Default

Idle time: disabled.
Server monitoring: disabled.
Timeout: 1 second.
Test username: test.
Test password: test.

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

You must use the feature tacacs+ command before you configure TACACS+.

When the idle time interval is 0 minutes, periodic TACACS+ server monitoring is not performed.

Examples

This example shows how to configure TACACS+ server host parameters:

switch(config)# tacacs-server host 192.168.2.3 key HostKey 
switch(config)# tacacs-server host tacacs2 key 0 abcd 
switch(config)# tacacs-server host tacacs3 key 7 1234 
switch(config)# tacacs-server host 192.168.2.3 test idle-time 10 
switch(config)# tacacs-server host 192.168.2.3 test username tester 
switch(config)# tacacs-server host 192.168.2.3 test password 2B9ka5 
 
   

Related Commands

Command
Description

feature tacacs+

Enables TACACS+.

show tacacs-server

Displays TACACS+ server information.


tacacs-server key

To configure a global TACACS+ shared secret key, use the tacacs-server key command. To remove a configured shared secret, use the no form of this command.

tacacs-server key [0 | 7] shared-secret

no tacacs-server key [0 | 7] shared-secret

Syntax Description

0

(Optional) Configures a preshared key specified in clear text to authenticate communication between the TACACS+ client and server. This is the default.

7

(Optional) Configures a preshared key specified in encrypted text to authenticate communication between the TACACS+ client and server.

shared-secret

Preshared key to authenticate communication between the TACACS+ client and server. The preshared key is alphanumeric, case sensitive, and has a maximum of 63 characters.


Command Default

None

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

You must configure the TACACS+ preshared key to authenticate the switch to the TACACS+ server. The length of the key is restricted to 65 characters and can include any printable ASCII characters (white spaces are not allowed). You can configure a global key to be used for all TACACS+ server configurations on the switch. You can override this global key assignment by using the key keyword in the tacacs-server host command.

You must use the feature tacacs+ command before you configure TACACS+.

Examples

This example shows how to display configure TACACS+ server shared keys:

switch(config)# tacacs-server key AnyWord 
switch(config)# tacacs-server key 0 AnyWord 
switch(config)# tacacs-server key 7 public 
 
   

Related Commands

Command
Description

feature tacacs+

Enables TACACS+.

show tacacs-server

Displays TACACS+ server information.


tacacs-server timeout

To specify the time between retransmissions to the TACACS+ servers, use the tacacs-server timeout command. To revert to the default, use the no form of this command.

tacacs-server timeout seconds

no tacacs-server timeout seconds

Syntax Description

seconds

Seconds between retransmissions to the TACACS+ server. The valid range is 1 to 60 seconds.


Command Default

1 second

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

You must use the feature tacacs+ command before you configure TACACS+.

Examples

This example shows how to configure the TACACS+ server timeout value:

switch(config)# tacacs-server timeout 3 
 
   

This example shows how to revert to the default TACACS+ server timeout value:

switch(config)# no tacacs-server timeout 3 
 
   

Related Commands

Command
Description

feature tacacs+

Enables TACACS+.

show tacacs-server

Displays TACACS+ server information.


telnet

To create a Telnet session using IPv4 on a Cisco Nexus 5000 Series switch, use the telnet command.

telnet {ipv4-address | hostname} [port-number] [vrf {vrf-name | default | management}]

Syntax Description

ipv4-address

IPv4 address of the remote switch.

hostname

Hostname of the remote switch. The name is alphanumeric, case sensitive, and has a maximum of 64 characters.

port-number

(Optional) Port number for the Telnet session. The range is from 1 to 65535.

vrf vrf-name

(Optional) Specifies the virtual routing and forwarding (VRF) name to use for the Telnet session. The name is case sensitive and can be a maximum of 32 alphanumeric characters.

default

Specifies the default VRF.

management

Specifies the management VRF.


Command Default

Port 23 is the default port.

Command Modes

EXEC mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

To create a Telnet session with IPv6 addressing, use the telnet6 command.

Examples

This example shows how to start a Telnet session using IPv4:

switch# telnet 192.168.1.1 vrf management 
switch# 
 
   

Related Commands

Command
Description

clear line

Clears Telnet sessions.

telnet server enable

Enables the Telnet server.

telnet6

Creates a Telnet session using IPv6 addressing.


telnet server enable

To enable the Telnet server, use the telnet server enable command. To disable the Telnet server, use the no form of this command.

telnet server enable

no telnet server enable

Syntax Description

This command has no arguments or keywords.

Command Default

Enable

Command Modes

Global configuration mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Examples

This example shows how to enable the Telnet server:

switch(config)# telnet server enable 
 
   

This example shows how to disable the Telnet server:

switch(config)# no telnet server enable 
 
   

Related Commands

Command
Description

show telnet server

Displays the Telnet server status.


telnet6

To create a Telnet session using IPv6 on the Cisco NX-OS switch, use the telnet6 command.

telnet6 {ipv6-address | hostname} [port-number] [vrf {vrf-name | default | management}]

Syntax Description

ipv6-address

IPv6 address of the remote device.

hostname

Hostname of the remote device. The name is alphanumeric, case sensitive, and has a maximum of 64 characters.

port-number

(Optional) Port number for the Telnet session. The range is from 1 to 65535.

vrf vrf-name

(Optional) Specifies the virtual routing and forwarding (VRF) name to use for the Telnet session. The name is case sensitive and can be a maximum of 32 alphanumeric characters.

default

Specifies the default VRF.

management

Specifies the management VRF.


Command Default

Port 23 is the default port. The default VRF is used.

Command Modes

EXEC mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

To use this command, you must enable the Telnet server using the telnet server enable command.

To create a Telnet session with IPv4 addressing, use the telnet command.

Examples

This example shows how to start a Telnet session using an IPv6 address:

switch# telnet6 2001:0DB8:0:0:E000::F vrf management 
switch# 
 
   

Related Commands

Command
Description

clear line

Clears Telnet sessions.

telnet

Creates a Telnet session using IPv4 addressing.

telnet server enable

Enables the Telnet server.