What is the Cisco IOS

• The Internetwork Operating System
• A Command-Line  method of configuring ANY Cisco Device
• Software that is consistent through nearly all Cisco Devices
• Learn it once, use it many times
• More powerful than any graphic interface

Connecting to the Cisco Switch

• Get a Console Cable
• Plug the Serial End into the back of your PC
• Plug the RJ-45 end into the Console Port on the BACK of the switch
• Open a Terminal Program
  • Hyperterm
  • Tera Term
  • Minicom
  • Securecrt
• Set it to connect via COM port with:
  • Baud Rate: 9600
  • Data Bits: 8
  • Parity: None
  • Stop Bits: 1
  • Flow Control: None

How to Get Help In The IOS

Type ? to see all commands available atm

— More —

To scroll one line at a time, press Enter

To scroll one page, press Space

To see all the commands that start with ‘c’ hit C?

To see all options available to a command, put a space between the command and the “?”:

clock ?

Up Arrow Recalls the previous command(s) entered.
To see all commands entered in the current mode:

show history

• This will show last 10 commands by default. Can be modified

ALL-CAPS = Variable

Terminal Shortcuts

You only need to type enough characters to identify the unique command.

Ambiguous command: "con"

To see all commands that start with “con” type:

con?
configure  connect

To see if there are any unique commands with the characters entered, press the [Tab] key (just like Linux!)

confTab
configure _

You can also enter shortcuts- just enough characters to be unique:
“conf t” = configure terminal
Ctrl+A – Move to Beginning of line
Ctrl+E – Move to End of line

If you enter invalid data, the system will let you know where you made the mistake:

# cloack
     ^
% Invalid input detected at '^' marker

Understanding The IOS Modes

User Exec (aka User Mode)

When you first enter into a Cisco device, you will be in “User Exec”
Identified by “>”
Basic Show commands, Telnet, Ping, etc. (Very Limited)

Privileged Exec (aka Privilege Mode)

> enable
# _

View anything on the switch.
See packets, view passwords, etc.
Show commands and same commands as in User Exec.
Only used to view, cannot perform any configurations.

Global Configuration

> configure terminal
(config)# _

From Global Configuration, you can enter any other mode available

Example: To enter “Interface Mode”
To return to Privilege Mode:

(config)# interface fastEthernet 0/1
(config-if)# _

To drop back to “Privilege Mode”

(config-if)# end
# _

To simply exit the current mode and back to Global:

(config-if)# exit
# _

“Exit” drops you back one level at a time.

“Bail Out Mode”
To exit out of everything and back to Privilege Exec:
Ctrl+Z

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