Cisco Device Configuration and Management
Cisco Device Configuration and Management tests practical Cisco IOS CLI skills: moving between command modes, setting device identity and passwords, enabling remote management, configuring interfaces and gateways, saving configuration, and verifying results with show commands.
Mode hierarchy and passwords
User EXEC (>) permits basic monitoring. Privileged EXEC (#) permits all show, reload, and copy commands and is reached with enable. Global configuration (config)# changes device-wide settings; interface, line, and router submodes change narrower settings. exit moves back one level and end returns to privileged EXEC; do show ... runs a show command from configuration mode. enable secret stores a hash and takes precedence over enable password. service password-encryption only weakly obscures plaintext passwords and is not a substitute for secrets.
SSH, interfaces, and gateways
For SSH, set hostname and ip domain-name, create local users with username name secret, configure line vty 0 4 with login local and transport input ssh, then generate keys with crypto key generate rsa modulus 2048. A Layer 2 switch management interface needs interface vlan 1 with an IP address, no shutdown, and ip default-gateway for off-subnet management. A router uses interface addresses plus ip route for a default route; ip default-gateway is not the router's default route. Save with copy running-config startup-config. Verify with show ip interface brief, show running-config, show startup-config, and show version.
Worked example
Configure SW1 for SSH management at 192.168.1.10/24 with gateway 192.168.1.1. Enter global configuration, set hostname SW1 and ip domain-name lab.local, create username admin secret, set enable secret, then configure interface vlan 1 with ip address 192.168.1.10 255.255.255.0 and no shutdown, and set ip default-gateway 192.168.1.1. Under line vty 0 4, use login local and transport input ssh. Generate RSA keys with modulus 2048 and save. The reasoning: key generation fails without a hostname and domain name; without login local the vty lines have no authentication; without the default gateway, management from another subnet fails.
Traps that cost marks
- Forgetting no shutdown leaves an interface administratively down.
- vty 0 4 covers five lines; vty 0 15 covers sixteen.
- SSH needs a hostname, domain name, local user, and generated key.
- Unsaved running configuration is lost on reload.
- The configuration register value affects the boot process; verify it before changing it.