CCNA Intro to the CLI (Day 4)
The command-line interface is the main tool used to configure network devices and becoming familiar to it will be important to my day-to-day.
After connecting a rollover cable to a console port on a router/switch/etc to a computer, we can use a terminal emulator such as PuTTy to enter the CLI and begin configuring our device.
(Note: the default speed of the serial line is 9600 bits, with data bits set to 8, stop bits set to 1, parity set to none, and flow control set to none.)
Process to get to global configuration mode for a device:
- Router>enable
- Router#configure terminal
- Router(config)#
Once in global configuration, we can set a case-sensitive password for getting into privileged exec mode (Router#) through the command:
- Router(config)#enable password [LINE]
Now, every time we enter terminal and run Router>enable we will be prompted to enter the password we created. However, this password is a security risk as it is saved in configuration as plain-text.
To have a more secure password using type 5 MD5 encryption we want to run the following command also from global configuration mode:
- Router(config)#enable secret [LINE]
This will automatically encrypt the password we give it with MD5 without having to use the service password-encryption command.
After any amount of configuration, we may want to save our running-config so on startup, our config will remain and won’t reset to default. we can do this through three commands from global config:
- Router(config)#write
- Router(config)#write memory
- Router(config)#copy running-config startup-config
All three options do the same exact thing — save the current running-config as the startup-config.
Packet Tracer examples:
