DAY 4 :: CLI

What two kinds of console ports are common on Cisco devices?

USB and RJ45

What kind of cable is used to connect to the RJ45 console port on a Cisco device?

Rollover cable

Default Cisco console port setting: Speed (baud rate)

9600 bits per second

Default Cisco console port setting: Data bits

8

Default Cisco console port setting: Stop bits

1

Default Cisco console port setting: Parity

None

Default Cisco console port setting: Flow control

None

In Cisco IOS' what symbol indicates user EXEC mode? (e.g. Router___)

>

In Cisco IOS' what symbol indicates privileged EXEC mode? (e.g. Router___)

#

In Cisco IOS' what indicates global configuration mode? (e.g. Router___)

(config)#

What is the lowest-level mode in Cisco IOS?

User EXEC mode

In Cisco IOS' which mode provides complete access to view the device's configuration files?

Privileged EXEC mode

Command to view the available commands at the current prompt

?

Command to enter privileged EXEC mode (from user EXEC mode)

enable

Command to enter global configuration mode (from privileged EXEC mode)

configure terminal

Command to configure an unencrypted password protecting privileged EXEC mode

enable password <password>

Command to return to privileged EXEC mode from global configuration mode

exit

What two configuration files are kept on a Cisco device?

running-config and startup-config

Command to view the running configuration

show running-config

Command to view the startup configuration

show startup-config

Which three commands can be used to save the running-config as the startup-config?

write / write memory / copy running-config startup-config

Command to encrypt current and future passwords stored on the device

service password-encryption

Command to configure an MD5-encrypted enable password

enable secret <password>

Which keyword lets you execute privileged EXEC commands while in global configuration mode (or other config modes)?

do

Which keyword is used in front of a command to remove/cancel it?

no (e.g. no service password-encryption)

What type of encryption does the service password-encryption command use?

Type 7

What type of encryption does enable secret use?

Type 5 (MD5)

If service password-encryption is later removed (no service password-encryption)' are already-encrypted passwords decrypted?

No — they remain encrypted

What does CLI stand for?

Command-Line Interface

What does GUI stand for?

Graphical User Interface

What is Cisco IOS?

The operating system used on Cisco devices (like Windows on a PC or macOS on a Mac)

Is Cisco's IOS related to Apple's iOS?

No — they are unrelated despite the similar name

What is an example of a Cisco GUI tool mentioned in the lesson?

Cisco ASDM (used to configure Cisco firewalls)

When you first set up a brand-new Cisco device' which connection method must you use?

A direct connection via the console port

On a rollover cable' pin 1 on one end connects to which pin on the other end?

Pin 8

On a rollover cable' pin 4 on one end connects to which pin on the other end?

Pin 5

What two connector types are on the ends of the cable used for RJ45 console connections?

RJ45 on one end' DB9 (serial) on the other

Since most modern laptops lack a serial port' what extra hardware is usually needed to console into a device?

A USB-to-serial (USB-to-DB9) adapter

What popular terminal emulator program is used to access the Cisco CLI through a console connection?

PuTTY

Where can you download PuTTY?

putty.org

In PuTTY' which connection type should be selected to console into a Cisco device?

Serial

What is the default hostname of an unconfigured Cisco router?

Router

What does pressing the Tab key do in the Cisco CLI?

Auto-completes the command currently being typed

What error does the CLI display if you type an abbreviation that matches more than one valid command?

% Ambiguous command

What is the shortest valid abbreviation for the enable command?

en

What is the shortest valid abbreviation for the exit command?

ex

What is the shortest valid abbreviation for configure terminal?

conf t

In the CLI' what does typing a word immediately followed by ? (no space) show?

All possible completions of that word

In the CLI' what does typing a command followed by a space and then ? show?

All the possible keywords/arguments you can type next

In CLI help output' what does <cr> mean?

That pressing Enter is a valid option' with no further arguments required

What happens if you enter the wrong enable password 3 times in a row?

You are denied access with a '% Bad secrets' message

Are Cisco IOS passwords case-sensitive?

Yes

Is type 7 encryption (from service password-encryption) considered secure?

No — it is a weak' proprietary algorithm that can be cracked quickly with freely available tools

If both enable password and enable secret are configured' which one does the router actually ask for?

Only the enable secret — the enable password is ignored

If you configure enable secret after already having an enable password' does the enable password command get deleted from the config?

No — it stays in the configuration but is ignored

Does the service password-encryption command have any effect on the enable secret password?

No — enable secret is always encrypted' regardless of service password-encryption

What network simulator software did Jeremy use to demonstrate the CLI in this lesson?

Cisco Packet Tracer

Why is a crossover cable NOT used to console into a Cisco device?

Crossover cables connect two similar Ethernet devices (e.g. switch-to-switch); they are wired differently than a rollover cable and aren't used for console access

Besides the RJ45 console port' what other console port type is found on many Cisco switches?

A USB mini-B console port

Which Cisco IOS mode is required in order to reload (restart) the device?

Privileged EXEC mode

Between enable password and enable secret' which should you always use in real-world/exam scenarios for best security?

enable secret — it is always strongly encrypted' unlike enable password

On a real Cisco device (vs. Packet Tracer)' would you expect more or fewer CLI commands to be available?

More — Packet Tracer is a simulator with limited command support

True or False: You must memorize full command names only' since shortcuts are not accepted on the real CCNA exam simulations.

False — both full commands and valid shortcuts work; just make sure you also know the full-length version of each command

What general command syntax pattern reverses/removes a previously configured setting in Cisco IOS?

Adding 'no' before the original command' e.g. no enable secret

Aside from console access' what other general category of connection method exists for accessing a Cisco device's CLI (covered in a later lesson)?

Remote access methods (e.g. Telnet/SSH)

If you disable password encryption using 'no service password-encryption'' what happens to newly configured passwords?

They will be stored in clear text (not encrypted)

What interactive prompt does a brand-new Cisco device ask to enter upon its first initial boot?

The initial configuration dialog (type 'no' to skip to the normal CLI)

Where is the running-config file actively stored while a Cisco device is powered on?

RAM (volatile memory; lost if the device reboots without saving)

Where is the startup-config file permanently stored on a Cisco device?

NVRAM (Non-Volatile RAM; preserved across reboots)

Where is the Cisco IOS operating system file itself typically stored on a Cisco device?

Flash memory

Which shortcut key combination lets you instantly exit back to privileged EXEC mode from any deep subconfiguration mode level?

Ctrl+Z (or typing 'end')

What error does the CLI display if you enter a completely unrecognizable or mistyped command?

% Unrecognized command