Good to know
With the “?”, you see what is expected next for each command.
The tab key is another lifesaver. It completes the command, if the IOS knows exactly what you want to enter, so you don’t have to type it all out. If the tab key does not work, there are more than one option so your command cannot be autocompleted.
| Functions | Terminal |
| User mode | Switch> |
| Privileged mode (after enabling it) | Switch# |
| Global configuration mode | Configure terminal |
| Interface configuration mode | Interface ethernet0/0 |
| Lists all interfaces with IP and status | Show ip interface brief |
| Changes the hostname | Hostname <> |
| Configure a banner before logging in | Banner motd = <YOURBANNERTEXT> = |
| Protecting privileged exec mode | enable secret 0 <PASSWORD> |
| protecting the console line | line console 0 password <PASSWORD> login |
| Restricting the VTY lines (the virtual lines) | line vty 0 4 password <PASSWORD> login transport input ssh |
| Obfuscate line passwords in config | Service password-encryption |
| Give switch a management ip | Interface vlan 1 Ip address 192.168.10.11 255.255.255.0 No shutdown |
| Give a port a description | Interface Gigabitethernet 1/0/1 Description “uplink to switch03” Exit |
| Save the configuration | wr |
| Lists interfaces with status, vlan, duplex and speed state | show interface status |
| Lists interfaces with its description so its not cut in half | show interface description |
| Lists all the mac addresses connected to the switch | show mac address-table |
| Let you search for one specific mac address | show mac address-table address ab12.cd34.ef56 |
Cisco Base configuration checklist
- Hostname
- Banner MOTD
- Enable secret
- Console password and login
- VTY password and remote access settings
- Service password-encryption
- Management IP on VLAN 1
- Port descriptions
- Saving the configuration
The Cisco boot process
- POST (Power-On Self Test)
First of all there is a self test which checks the hardware components. - Bootstrap Program Initialization
Once POST completes successfully the Bootstrap program stored in ROM is loaded and executed. It initialises the basic hardware. - Locating and Loading the IOS
Based on the configuration register the bootstrap program locates the Cisco IOS and loads it into RAM. - Loading the config file
When IOS is fully operational the devices searches the NVRAM for a saved configuration file. If its found it’s loaded into RAM. If not the device prompts the user for setup configuration wizard. - Final initialization
When the IOS is loaded and conigs are applied the hardware interfaces are initialized and the device opens in user exec mode.
Saving or resetting Cisco configurations
Your device is dealing with two types of storage. The RAM and the NVRAM. The running configuration is living in RAM that means if you type “reload” the switch loses what is in RAM so that config would be deleted (if not saved earlier). If you want to delete a startup config (which lives in NVRAM) you can type “write erase”. So the startup config is deleted, but are we done? Not quite yet. We probably still have a running config loaded into RAM which is currently working. So how can we get rid of these? Correct, we reboot the switch and we successfully reset our config.