Configuration Commands

end

Exits configuration mode and goes back to enable mode from any of the configuration submodes.

line console 0

Global command that changes the context to console configuration mode.

interface type port-number

Global command that changes the context to interface mode—for example, interface FastEthernet 0/1.

line vty 1st-vty last-vty

Global command that changes the context to vty configuration mode for the range of vty lines listed in the command.

hostname name

Global command that sets this switch's host name, which is also used as the first part of the switch's command prompt.

password pass-value

Line (console and vty) configuration mode. Lists the password required if the login command (with no other parameters) is configured.

login

Line (console and vty) configuration mode. Tells IOS to prompt for a password (no username).

exit

Moves back to the next higher mode in configuration mode.

Router(config-line)# access-class access-list-number {in | out}

The access-class command is used to restrict incoming and outgoing connections between a VTY and the address in an access list. This command is issued in line configuration mode. The syntax of the command is as follows: Router(config-line)# access-class access-list-number {in | out} The parameters of the command are as follows: access-list-number: Specifies the number of an IP access list. in: Restricts the incoming connections. out: Restricts the outgoing connections.

Router(config)# ip access-list {standard | extended} access-list-name

The ip access-list command is used to define an access list by name. This command is issued in the global configuration mode. The correct syntax of the command is as follows: Router(config)# ip access-list {standard | extended} access-list-name The parameters of the command are as follows: standard: Specifies an standard IP access list. extended: Specifies an extended IP access list. access-list-name: Specifies the name of the access list.

neighbor {ip-address | peer-group-name} password {string}

The neighbor password command is used to activate MD5 authentication on a TCP connection between two BGP peers. The complete syntax of this command is: neighbor {ip-address | peer-group-name} password {string} The parameters are defined as follows: ip address: Refers to the IP address of the BGP-speaking neighbor. peer-group-name: Refers to the name of the BGP peer group. string: The case-sensitive password. Passwords can be up to 25 characters if the service password-encryption command is enabled, or up to 81 characters if it is not enabled. The string can contain alphanumeric characters, including spaces, but the first character in the string cannot be a number or a number followed by a space. The service password-encryption command is incorrect because this command is used to encrypt passwords. The key-string command is incorrect because this command is used to configure the authentication string for a key. The authentication MD5 BGP command is incorrect because this is not a valid Cisco IOS command.

router(config-if)# ip access-group {access-list-number|access-list-name} {out|in}

The router(config-if)# ip access-group command is used to apply an access list to an interface. This command is issued in interface configuration mode. The syntax of the command is as follows: router(config-if)# ip access-group {access-list-number|access-list-name} {out|in} The parameters of the command are as follows: out|in: Specifies where the access list will be applied on the router. The out value will cause the router to apply the access list to all outgoing packets. The in value will cause the router to apply the access list to all incoming packets. access-list-number: Specifies the number of an access list. access-list-name: Specifies the name of the access list.

Ctrl-Z

This is not a command, but rather a two-key combination (pressing the Ctrl key and the letter Z) that together do the same thing as the end command.

show cdp neighbors

displays detailed information about neighboring devices discovered by the CDP. However, it does not include the IP address of the neighboring device.

show cdp

displays global CDP information, including timer and hold time information.

show cdp interface

displays information about the interfaces on which CDP is enabled.

show cdp neighbors detail

displays the Cisco devices directly connected to the router. The detail keyword in the show cdp neighbor command also displays IP address information for the directly connected devices. The output shows the connected device name, its IP address, its platform, and the local interface through which the device is connected.

show frame-relay pvc

used to verify the PVC status or to view the encapsulation type. The information displayed by this command is related to the Data Link Connection Identifier (DLCI) assigned to the connection and the status of the connection. This command would appropriate if the DLCI were inactive. It will not shed any light on the encapsulation used.

show frame-relay map

used to view the encapsulation currently configured on both the devices