Using CLI Flashcards
Cabling the console connection
Consist of three main components
- Physical console port on the switch
- Physical serial port on the PC
- Cable that works with console and serial ports
Different forms of connection
SW1 - Host
- RJ45 Console on SW1
- Rollover cable
- Serial port on Host
SW2 - Host
- RJ45 Console on SW2
- Rollover cable
- USB Converter, USB Cable
- USB Port on Host
SW3 - Host
- USB Console on SW3
- USB Cable
- USB Port on Host
Console port settings
- 9600bits/s
- No hardware flow control
- 8 bit ASCII
- No parity bits
- 1 stop bit
Accessing CLI with Telnet
Telnet allows user to connect to another device’s CLI, Traffic flows over the same IP network that the network the devices are working on
Telnet uses the concept of a telnet client and a telnet server. A telnet client, accepts keyboard input from user and send those commands to the Telnet server. Telnet server accepts the text, interprets the text as a command and replies back
Issue with Telnet
Poses a security risk in production network, sends all data as clear text data
Pros of SSH
SSH is a more secure version of Telnet, encrypts the contents of all messages, including the passwords, avoiding the possibility of someone capturing packets in the network and stealing the password
Three CLI access mode
EXEC mode - Allows the user to look around but not break anything
Enable mode - Moves the user from user mode to enable mode, allow powerful commands to be executed
Both mode above does not disrupt switch operations or config
Global Config mode - Commands that tell the switch the details of what to do and how to do it
Reload command
reload
Tells the switch to reinitialize or reboot IOS
Show running-config
Lists the current config in the switch
Enable secret love
Defines the password that all users must use to reach enable mode
line console 0
A command that identifies the console, “basically the next few commands apply to the console only”
login
Commands tells IOS to perform simple password checking
password
Defines the password the console user must type when prompted
Help features
? - All commands
command ? - describe all the first parameter option for the command
Help features are mode specific
debug and show commands
show, find the current status and list the information in messages sent to the user
show mac address-table dynamic
show all mac address in a table
Global config submodes
Entering Global Config Mode:
1. config t
Accessing:
- interfaces, int fa 0/1
- line, line console 0, line vty 0 15
- Vlan, vlan
Configuration:
- hostname, hostname
- password, password hope (After entering into console)
- speed, speed (After entering interface)
Example Command
configure terminal hostname Fred line console 0 password hope interface fa 0/1 speed 100 exit
Storing Switch Config Files (Memory Components) (4 Types)
- RAM; dynamic random access memory, RAM is used by the switch as a WORKING STORAGE; Stores the running config
- Flash Memory; Flash memory stores fully functional Cisco IOS images, Is the default location where the switch gets its Cisco IOS at boot time, Stores also the backup copies of config files
- ROM; Read only memory - Stores a bootstrap program that is loaded when the switch first power on
Bootstrap program finds the full Cisco IOS image and manages the process of loading Cisco IOS into RAM, at which point Cisco IOS takes over ops of the switch - NVRAM; Nonvolatile RAM stores the initial or startup configuration file that is used when the switch is first powered on and when the switch is reloaded
Configuration File Purpose ( 2 Types )
- startup-config; Stores the initial configuration used anytime the switch reloads Cisco IOS
- running-config; Stores the currently used config command, Changes dynamically; Lost when power off
Copying & Erasing Config Files
- Copy, copy running-config startup-config
- Erasing existing startup-config
write erase
erase startup-config
erase nvram
