Using cisco CCNA command lines

1. Using the Command-Line
Interface
This topic is very important before you configure or verify the cisco
router and switches.
CLI – Command Line Interface
No specific exam topics included in this chapter.
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2. Accessing the Cisco Catalyst Switch CLI
• CLI – Command Line Interface:
• The CLI is a text-based interface in which the user, typically a network engineer, enters a text
command and presses Enter.
• Pressing Enter send a command to the brain of the device i.e., Control Plane, to do something.
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3. Cisco Catalyst Switches
• 2960-XR model is the leading switch manufactured by Cisco
• Cisco refers to a switch’s physical connectors as either interfaces or ports.
• Normally called as Ethernet, Fast Ethernet, Gigabit Ethernet – 10 , 100 ,1000.
• Namings :
• Its always good to name them with Fa Slot/Port ex., Fa 0/1 or Fa0/2 sometimes Fa FPC/Slot/Port
Slot 0
Slot 1
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4. Accessing the Cisco IOS CLI
• Like any other hardware’s, cisco also needs Operating System and we call it as IOS – Internetwork
Operating System
The switch CLI can be accessed through three popular methods
1.Console – Using a Serial cable one end to the router other end to PC
2. Telnet – Remote access - Not Encrypted. – Port Number 23
3. SSH - Remote access – Encrypted - Port Number 22
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5. Cabling the Console Connection
• The connections can be with RJ45, USB Port, USB Console
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6. • The default console port settings on a switch are as follows.
9600 bits/second
No hardware flow control
8-bit ASCII
No parity bits
1 stop bit
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7. Accessing the CLI with Telnet and SSH
• Telnet uses the concept of a Telnet client (the terminal application) and a Telnet server (the switch in this
case).
• SSH encrypts the contents of all messages, including the passwords, avoiding the possibility of someone
capturing packets in the network and stealing the password to network devices.
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8. User and Enable (Privileged) Modes
• When we access the device by any of the above 3 methods the CLI places the user in User Exec mode or
user mode, allows the user to look around but not break anything.
• Exec mode is self explanatory You enter a command and it will display something.
• More Powerful Exec mode is Privileged mode or enable mode, this name came because we have to type
enable from user mode to move to this mode.
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9. Password Security for CLI Access from the Console
• Passwords can be configured in two modes 1. When someone login 2. When they move to any other
modes.
• The enable secret love configuration command defines the password that all users must use to reach
enable mode.
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10. Practical Demo Rec 4
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11. Cisco IOS Software Command Help
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13. The debug and show Commands
• Show commands is the one of most important and famous command.
• It has a large variety of options, and with those options, you can find the status of almost every feature of
Cisco IOS.
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14. Configuring Cisco IOS Software
• Configuration mode is another mode for the Cisco CLI, similar to user mode and privileged mode.
• User mode ( R1> ) lets you issue nondisruptive commands and displays some information.
• Privileged mode ( R1# ) supports a superset of commands compared to user mode, including commands that
might disrupt switch operations.
• Configuration mode ( R1(config)) accepts configuration commands
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15. Different Configuration Modes
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17. Storing Switch Configuration Files
• When you configure a switch, it needs to use the configuration. It also needs to be able to retain the
configuration in case the switch loses power.
• Think RAM IS A VOLATILE MEMORY
Devices have following other types of Memory
1. Flash - Stores Fully functional IOS image
2. ROM - Loads Cisco IOS image into RAM when we boot the device
3. NVRAM - Stores the initial or startup configuration file
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19. Erase Startup config
• You can erase the entire startup config by using below command.
R1#erase startup-config
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20. Command Reference
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