Configuring, commands and theory behind them. Flashcards
Explain what these modes allow. which symbol they have and how to go between them
User EXEC Mode
Priviliged EXEC Mode
Global Configuration Mode
Line Configuration Mode
Interface Configuration mode
- User EXEC Mode
- Used to access configuration options on the device
Priviliged EXEC Mode
Allows access to all commands and features.
Identified by the #
enable or exit from others
Global Configuration Mode
-Used to access configuration options on the device
Identified by config
Configure terminal
Line Configuration Mode
Used to configure console,SSH,Telnet or AUX access
line console 0
Interface Configuration mode
-Used to configre a switch port or router interface
interface (interface u want to access)
What can you do to get more information about a command?
Use “?”
Example Ping?
Word, Ip, Ipv6
What does the term “basic device configuration” mean? (Not router)
The different commands u need to use to configure a device.
Configure Hostname
Device(config)# hostname Device
Secure Privileged EXEC mode
Device(config)# enable secret password
Secure EXEC mode
Device(config)# line console 0
Device(config-line)# password password
Device(config-line)# login
Securing VTY line access:
Device(config-line)#line vty 0 15
Device(config-line)#password “password”
Device(config-line)#login
Device(config-line)#end
Device(config-line)#service password encryption
Device(config-line)#banner motd #message of the day#
Which config files do we have, how do you save them?
startup-config, saved in NVRAM
running-config, saved in RAM
copy running-config
startup-config
What is in Basic Router Configuration
Configure Hostname
R1(config)# hostname R1
Secure Privileged EXEC mode
Router(config)# enable secret password
Secure EXEC mode
Router(config)# line console 0
Router(config-line)# password password
Router(config-line)# login
Secure remote Telnet/SSH access.
Router(config)# line vty 0 4
Router(config-line)# password password
Router(config-line)# login
Router(config-line)# transport input {ssh | telnet}
Encrypt all plaintext passwords.
Router(config)# service password encryption
Provide legal notification and
save the configuration.
Router(config)# banner motd # message #
Router(config)# end
Router# copy running-config startup-config
How do you configure a router interface?
Choose interface
Router(config)# interface type-and-number
Give description
Router(config-if)# description description-text
Configure Ipv4 address with subnet mask and ipv6 address with prefix length
Router(config-if)# ip address ipv4-address subnet-mask
Router(config-if)# ipv6 address ipv6-address/prefix-length
Activate interface
Router(config-if)# no shutdown
Example
R1(config)# interface gigabitEthernet 0/0/0
R1(config-if)# description Link to LAN
R1(config-if)# ip address 192.168.10.1 255.255.255.0
R1(config-if)# ipv6 address 2001:db8:acad:10::1/64
R1(config-if)# no shutdown
R1(config-if)# exit
R1(config)#
*Aug 1 01:43:53.435: %LINK-3-UPDOWN: Interface GigabitEthernet0/0/0, changed state to down
*Aug 1 01:43:56.447: %LINK-3-UPDOWN: Interface GigabitEthernet0/0/0, changed state to up
*Aug 1 01:43:57.447: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/0,
changed state to up
What are the verification commands for interface? And what they show
Displays all interfaces, their IP addresses, and their current
status.
show ip interface brief
show ipv6 interface brief
Shows info about IP routing tables in RAM
show ip route
show ipv6 route
Displays statistics for all interfaces on the device. Only
displays the IPv4 addressing information
show interfaces
Displays the IPv4 statistics for all interfaces on a router.
show ip interfaces
Displays the IPv6 statistics for all interfaces on a router.
show ipv6 interfaces
How to configure Default Gateway on a switch
ip default-gateway ip-address
Which 5 boot steps does a Cisco switch go through after being powered on?
- POST(Power on self-test) stored in ROMChecks CPU, DRAM and portion of the flash device that makes upm the flash file system.
- Loads boot-loader, program stored in ROM that runs immediately after POST
- Boot loader performs low-level CPU initializatio. Initializes CPU registers, physical memory mapping , quantity of memor and speed.
- Boot loader initizalizes the flash file system on the system board.
- Boot loader locates and loads default IOS operating system software image into memory and gives control of the switch over to the IOS.
How does the switch try to boot?
Switch attemps to automatically boot by using information in the BOOT environment variable, If this variable is not set, the swith happends to load and execute the first exectuble it can find.
The IOS operating system then initialzes the inferfaces using the Cisco IOS commands found in the startup-config file called config.txt and is located in flash.
Which LED indicatos does a switch have?
System LED (SYST): Functioning properly and getting power.
Redunants Power Supply LED(Shows the RPS status) (external power)
Port Status LED (STAT) If green, indicates port status mode is selected, default.
Port Duplex LED (DUPLX) When green, indicates port duplex mode is selected.
PORT Speed LED (SPEED)( When green, indicates port speed mode is selected.
Power over Ethernet LED (PoE) PoE status on the switch
The Mode button is used to move between the different modes – STAT,
DUPLX, SPEED, and PoE
How does a switch recover from a system crash?
- Connect PC by console cable. Use terminal emulation software to connect to the switch.
- Unplug the power
- Reconnect power, after 15 seconds, hold down mode while the SYSTEM LED is flashing green.
- Hold mode until System LED turns briefly amber and theng green.
5.The boot loader switch: prompt appears in terminal on PC.
Format flash file system, reinstall OS, recover lost or forgotten password.
What do you need to do before u can have remote management access on a switch?
The switch must be configured with an IP address(default gateway) and a subnet mask
Also consle cable
What are the steps to configuring SWITCH SVI? Which commands are being used?
- Configure management interface for Ipv4 and IPv6
S1# configure terminal
S1(config)# interface vlan 99
S1(config-if)# ip address 172.17.99.11 255.255.255.0
S1(config-if)# ipv6 address 2001:db8:acad:99::1/64
S1(config-if)# no shutdown
S1(config-if)# end
S1# copy running-config startup-config
2.Configure Default Gateway S1# configure terminal S1(config)# ip default-gateway 172.17.99.1 S1(config-if)# end S1# copy running-config startup-config
3.Verify Configuration
show ip interface brief
show ipv6 interface brief
Why is Full-Duplex useful, and half-duplex not so much <3 ?
Increases bandwidth efficiency by allowing both enbds of a connection to transmit and receive data simultaneously. Gigabit Ethernet and 10Gb NICs require full-duplex to operate. Collision detection gets disabled on NIC and Full-Duplex offers 100% efficiency.
Half-duplex communication is unidirectional. Creates performance issues because data can flow in only one direction at a time, resulting in collisions.
How to configure Full Duplex mode on a switch
Enter global configuration mode.
S1# configure terminal
Enter interface configuration mode.
S1(config)# interface FastEthernet 0/1
Configure the interface duplex and interface speed
S1(config-if)# duplex full
S1(config-if)# speed 100
Return to the privileged EXEC mode and save running config to startup config.
S1(config-if)# end
S1# copy running-config startup-config
What is Auto-MDIX? How do we configure it and check the settings on a specific interface=
When auto-MDIX is enabled, the interface automatically detects the required cable connection type (straight-through or crossover) and configures the connection appropriately.
S1(config-if)# mdix auto
S1# show controllers ethernet-controller fa0/1 phy | include MDIX
What are the 8 switch verification commands? What do they do?
Display interface status and configuration. S1# show interfaces [interface-id]
Display current startup configuration. S1# show startup-config
Display current running configuration. S1# show running-config
Display information about flash file system. S1# show flash
Display system hardware and software status. S1# show version
Display history of command entered. S1# show history
Display IP information about an interface.
S1# show ip interface [interface-id]
OR
S1# show ipv6 interface [interface-id]
Display the MAC address table.
S1# show mac-address-table
OR
S1# show mac address-table
Which Interface Input and Output Errors do we have?
Input Errors . Number of errors
Runts: Packets discarded becasue thy are smaller than minimum packet size for the medium
Giants: Too big for medium
CRC: Checksum is not the same as checksum received
Output errors: Sum of all errors that prevented the final transmission of datagrams
Collisions: Number of messages retransmieed because of collision
Late collisions: A collision that occurs after 512 bits of the frame has been transmitted.
What is Telnet?
Telnet is an older protocol that uses unsecure plaintext transmission of both the login authentication and the data transmitted between the communicating devies. Port 23
What is Secure Shell SSH? How to configure it? Verify if operational
Secure Shell(SSH) is a secure protocol that uses TCP port 22. SSH provides security for remote connections by providing strong encryption when a device is authenticated and also the transmitted data between the communicating devices.
1.Verify SSH Support
S1# show ip ssh
2.Configure IP domain.
S1(config)# ip domain-name cisco.com
3.Generate RSA key pairs.
S1(config)# crypto key generate rsa
How many bits in the modulus [512]: 1024 (Longer is more secure, but it takes longer to generate and to use.
4Configure user authentication.
S1(config)# username admin secret ccna
5Configure the vty lines. S1(config)# line vty 0 15 S1(config-line)# transport input ssh S1(config-line)# login local S1(config-line)# exit
Enable SSH version 2.
S1(config)# ip ssh version 2
show ip ssh
show ssh
What is Ipv4 Loopback Interfaces used for? How do you configure them?
Used to identify the device.
Router(config)# interface loopback number
Router(config-if)# ip address ip-address subnet-mask
What is extended ping and extended traceroute.
When you just write ping without destination IP. You will then be given several promts to customize the extended ping.
Same with traceroute
How do we assign a VLAN to the correct interfaces?
Enter global configuration mode.
Switch# configure terminal
Enter interface configuration mode.
Switch(config)# interface interface-id
Set the port to access mode.
Switch(config-if)# switchport mode
access
Assign the port to a VLAN.
Switch(config-if)# switchport access vlan vlan-id
Return to the privileged EXEC mode.
Switch(config-if)# end
example: S1# Configure terminal S1(config)# Interface fa0/18 S1(config-if)# Switchport mode access S1(config-if)# Switchport access vlan 20 S1(config-if)# end
