Chapter 5: Securing Network Devices

line console 0

Command that changes the context to console configuration mode.

line vty 0 4

Command that changes the context to vty configuration mode for lines 0 through 4.

login

Console and vty configuration mode command that tells IOS to prompt for a password.

password P@ssw0rd!

Console and vty configuration mode command that lists the password required if the login command is configured.

login local

Console and vty configuration mode command that tells IOS to prompt for a username and password, checked against locally configured usernames.

username netadmin algorithm-type sha256 secret S3eCur3tH4sh!

Global command defining username netadmin with a SHA256-hashed password.

username guest password Guest123!

Global command defining username guest with a clear-text password (Guest123!) stored in the configuration.

crypto key generate rsa modulus 1024

Global command to generate RSA keys with a 1024-bit modulus, required for SSH.

transport input ssh

VTY line configuration command that allows only SSH access into the switch.

service password-encryption

Global command that encrypts all clear-text passwords in the running configuration.

enable password Enable123

Global command to create the password (Enable123) stored as clear text.

enable secret S3cr3tEnaBle

Global command to create the enable password (S3cr3tEnaBle) stored as a hashed value.

no enable secret

Global command to remove the enable secret from the configuration.

no enable password

Global command to remove the enable password from the configuration.

access-class 15 in

VTY line subcommand that applies ACL 15 inbound to Telnet and SSH connections.

show running-config | section vty

EXEC command that lists vty line configurations and their subcommands from the running configuration.

show running-config | section con

EXEC command that lists console line configuration and subcommands from the running configuration.

show running-config | include enable

EXEC command that displays all lines in the running configuration containing the word “enable”.