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Friday, January 8, 2021

 

Contents Index:

 

Cisco networking device’s Operating System:  Each hardware device has an Operating system such as windows, Linux, macOS. Operating systems are required for making hardware device interactive between application software and user. Hence every cisco networking device requires an operating system that is named the Internetwork Operating System (IOS). Two types of secondary memory unit are in router and switch. There are Flash memory and NVRAM. Cisco IOS is located in flash memory. NVRAM is another type of secondary memory which is specific for storing a startup configuration file.

Router and switch configuration mode: For configuring switch and router networking device, two major configuration mode have to be known to all.

Two main configuration mode are:

  •        User Exec mode
  •        Privileged Exec mode

To configure the device, the Administrator must enter to Global Configuration mode referred to as global config mode. There are two sub-configuration modes referred to as line-configuration mode and interface-configuration mode. For configuring interfaces of router and switch, interface configuration mode is required as well as to configure console, SSH connects, line-configuration mode is required. For security reason, Cisco IOS separates whole management mode into these various modes.

User Exec mode: In this mode, very few monitoring commands can be executed. That’s why it is referred to as “view-only” mode. The mode can be identified by examining the Command Line The interface of Cisco IOS. In the CLI of a switch networking device, “switch >” indicates User Exec mode. As well as “router>” indicates User Exec mode of router intermediary device.

Privileged Exec Mode: This the main authorized mode. The administrator has to access this mode to perform all commands and features and can utilize any display commands and management commands. The mode can be identified by examining the Command Line Interface of Cisco IOS. In the CLI of a switch networking device, “switch#” indicates privilege Exec mode. As well as “router#” indicates Privilege Exec mode of router intermediary device.

Navigation among various modes: Several commands are used to move to and from different modes. By default, the device’s CLI program holds on User Exec mode on starting of the program. To enter privileged EXEC mode from User Exec mode, enable command is used and to back from privilege to user Exec mode, disable command is required to enter.


Switch> enable

Switch#

Switch#configure terminal

Switch(config)#

Switch(config)#interface fa0/0

Switch(config-if)#

Switch(config)#line console 0

Switch(config-line)#

Router> enable

Router#

Router#configure terminal

Router(config)#

Router(config)#interface fa0/0

Router(config-if)#

Router(config)#line console 0

Router(config-line)#


To get entered into global configuration mode, configure terminal privilege Exec command is required. Then to enter sub-configuration mode, interface and line commands are required. To move from any sub-configuration mode to the privileged EXEC mode, enter the end command or enter the key combination “Ctrl+Z”.

 

Basic commands for the router to ready to use:

Set hostname: --> (config)#

hostname [name]

set domain name: --> (config)#

IP domain-name know-inform.blogspot.com

Set Banner: -->(config)#

banner motd $This is Router$

 

Device Hardening:

Console line security --> (config-line)#

line console 0

password cisco12345

login

logging synchronous

exec-timeout 60

exit

 

Privileged Exec level security -->(config)#

enable secret class12345

service password-encryption

security passwords min-length 10

login block-for 120 attempts 2 within 30

crypto key generate rsa general-key modulus 1024

 

Remote access level security -->(config-line)#

line vty 0 4

password cisco12345

transport input ssh

login local

logging synchronous

exec-timeout 60

exit

 

line aux 0

password cisco12345

login

logging synchronous

exec-timeout 60

exit

 

creating Local database: --> (config)#

username [admin] privilege 15 secret [Cisco_CCNA7]




References:

1. Cisco- Cisco Certified Network Associated Course Contents

2. Cisco Website

 

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