Cisco Command Notes

What does the “enable” do?

It grants access to Privileged EXEC mode.

What configuration level is this? R1>

This is User EXEC mode, where basic commands can be executed but no configuration changes can be made.

What configuration level is this? R1#

This is Privileged EXEC mode, allowing access to more advanced commands and configuration options.

What configuration level is this? R1config#

This is Global Configuration mode, where you can make changes to the router's configuration.

What configuration level is this? R1config-int#

This is Interface Configuration mode, used to configure settings specific to a particular network interface on the router.

At what level is the enable command used at?

User EXEC mode

Whats the command to disable DNS lookup on a Cisco device?

“no ip domain-lookup”

At what level is the command to disable DNS lookup configured at?

Global configuration mode

What command is used to set the name of a Cisco device?

'hostname [router_name]'.

At what level is the name of a host configured at?

Global configuration mode

What’s the command to encrypt all plain-text passwords stored in configuration?

The command to encrypt all plain-text passwords is 'service password-encryption.'

At what level is the command to encrypt all plain-text passwords configured at?

Global configuration mode.

What’s the command to create a banner to prohibit unauthorized access?

Use the command 'banner motd #[your message]#'.

What command do you use to set a local user with a secret password?

'username [username] secret [password]'.

Why should you use the “Login” command after configuring a password on the console and VTY lines?

The "Login" command enables password checking on the console and VTY lines, ensuring that users must input their password to gain access.

How do you configure the console line for local login?

Use 'line console 0', followed by 'login local'.

When should the “login local” command be used?

Use login local when you want the device to authenticate users using the local username and password database (after creating a username with the username command).

Which login method is required for SSH access on a router?

login local — because SSH requires a username and password from the local user database.

What is the difference between login and login local?

Login uses the line password only.

Login local uses a username and password from the local user database.

What happens if you create a username but do NOT configure login local?

The username will not be used for authentication, and login will fail or fall back to line password (if configured).

What command configures SSH on a Cisco device to force version 2?

Use 'ip ssh version 2'.

How do you set an IPv4 address on an interface?

Use 'ip address [ip_address] [subnet_mask]'.

What is the command to enable a specific interface?

Use 'no shutdown'.

What’s the command to configure a default gateway on a switch?

Use 'ip default-gateway [gateway address]'.

What command shows a brief summary of the IP interfaces?

Use 'show ip interface brief'.

How do you test connectivity to an IP address?

Use the 'ping [IP address]' command.

What command is used to generate RSA keys for SSH?

Use 'crypto key generate rsa [key_size]'.