Cisco CCNA Command Summary

Describe

Command

User mode

Switch>

Enter Privilege mode

Switch>enable

Privileged mode

Switch#

Enter configuration mode

Switch#configure terminal

Global Config mode

Switch(config)#

Enter Interface mode

Switch(config)#interface fa0/1

Interface mode

Switch(config-if)

Return to global configuration (Return to Global Config)

Switch(config-if)exit

Exit Global Config mode

Switch(config)#exit

Return to user mode

Switch#disable

Logout

Switch>exit

Describe

Shortcuts

Recall Previous command (Call Previous command)

Up arrow or p

Recall Next command

Down arrow or n

Start command

a

End of command

e

Delete input

d

Exit Configuration Mode

z

Refresh the output on the screen

R

Complete the order

TAB

Describe

Command

Configure device system name

Switch(config)#hostname sw1

Sets the encrypted enable password

Switch(config)#enable secret cisco

Sets the unencrypted enable password

Switch(config)#enable password cisco

Enable password encryption on all clear text password within the configuration file

Switch(config)#service password-encryption

Configure a Message Of The Banner, with an ending character of $

Switch(config)#banner motd $

Assign IP address to vlan (assign ip to vlan)

Switch(config)#int vlan 1

Switch(config-if)#ip addr 172.22.1.11

255.255.255.0

Assign Default gateway, note the mode: assign default gateway.

Switch(config)#ip default-gateway 10.1.1.1

Select one interface: select 1 interface.

Switch(config)#int fa0/1

Select a range of interfaces (version dependent): select a range of interfaces.

Switch(config)#int range fa0/1 – 12

Set the interface description: Write a description for the interface.

Switch(config-if)#description

Add vlan using config mode: add vlan using config mode.

switch(config)#vlan 11 switch(config-vlan)#name test

Configure Interface fa0/1 @ speed 100 Mbps and full duplex: Configure int fa0/1 @ speed 100Mbps and full duplex.

Switch(config-if)#speed 100 Switch(config-if)#duplex full

Assign interface to vlan: assign int to vlan.

switch(config-if)#switchport access vlan 11

Enable Port Security: Enable port security.

Switch(config-if)#switchport mode access Switch(config-if)#switchport port-security Switch(config-if)#switchport port-security mac-address sticky

Disable Interface: disable int

Switch(config-if)shutdown

Enable Interface: allows int operations.

Switch(config-if)no shutdown

Configures 5 Telnet sessions each with a password of 'cisco': allows 5 Telnet sessions at a time, password is cisco.

Switch(config)#line vty 0 4

Switch(config-line)#login

Switch(config-line)#password cisco

Enable and define console password of 'cisco': Enable and define console password of 'cisco'.

Switch(config)#line child 0

Switch(config-line)#login

Switch(config-line)#password cisco

Synchronise console messages (keep what you have typing on the screen): Synchronise console messages, keep what you have typing on the screen.

Switch(config-line)#logging synchronous

Set the timezone and automatically adjust: Set the timezone and automatically adjust.

Switch(config)#clock timezone gmt 0 Switch(config)#clock summer-time gmt recurring

Sets the switch priority for the vlan: Sets the priority for the vlan.

Switch(config)#spanning-tree vlan 1 priority 4096

Enables portfast: Enables portfast.

Switch(config)#int fa0/1

Switch(config-if)#spanning-tree portfast

Enables RSTP: Enables RSTP, other options are PVST and MST.

Switch(config)#spanning-tree mode rapid-pvst

Creates a vlan: Creates a vlan. This command is executed in config mode, not in the vlan database, and the int vlan command does not create a vlan.

Switch(config)#vlan 2 Switch(config-vlan)#name sales

Assign an interface to vlan 2: Assign int to vlan 2.

Switch(config-if)#switchport access vlan 2

Force int to be trunk unconditionally. Other modes available are access and dynamic.

Switch(config-if)#switchport mode trunk

Manually assign a switch to a VTP domain. A switch automatically becomes part of a VTP domain if it is in a "null" domain and receives a VTP frame.

Switch(config)#vtp domain lab

Change VTP mode from default server to client. It cannot be changed in client mode.

Switch(config)#vtp mode client

Set the enable secret password to peter:

Set the secret password to peter. This password overrides the enable password and is encrypted in the configuration file.

Enable the http server to SDM can be used: Enable the http server to use SDM.

Router(config)#ip http server

Defines a username and password: Sets a username (sue) and password (cisco). Can be used for PPP authentication or user access.

Router(config)#username sue password cisco

Define local hosts file in unix, like:

/etc/hosts in unix

Router(config)#ip host mypc 10.1.1.3

Disables DNS lookup. Useful when commands are mistyped.

Router(config)#no ip domain-lookup

Sets the logical (not physical) bandwidth for the interface. Commonly used by routing protocols, SNMP queries.

Router(config)#int s0

Router(config-if)#bandwidth

Set physical clock

Router(config-if)#clock rate 64000

Set the serial interface WAN encapsulation: In addition to hdlc, other options are PPP and frame-relay.

Router(config-if)#encapsulation hdlc

Authentication on PPP is optional: This command enables chap on the interface, the other option is PAP.

Router(config-if)#ppp authentication chap

Select LMI type. If LMI type is not configured correctly it will be detected automatically.

Router(config-if)#frame-relay lmi-type cisco

Static routing. Static routing type has Administrative Distance (AD) of 1, so it will override any dynamic routing.

Router(config)#ip route 50.0.0.0 255.0.0.0

10.1.2.1

Enables RIP version 1 on all LOCAL interfaces which have a 10.xxx address: Enables RIP v1 on all LOCAL interfaces which have a 10.xxx address

Enables RIP version 2: Enable RIP v2

Router(config)#router rip

Router(config-router)#network 10.0.0.0

Router(config-router)#version 2

Enable the router to provide a DHCP service: Set up DHCP on the router.

Router(config)#ip dhcp pool MYPOOL

Router(dhcp-config)#network 10.1.1.0 255.255.255.0

Router(dhcp-config)#default-router 10.1.1.1 Router(dhcp-config)#exit

Router(config)#ip dhcp excluded-address 10.1.1.1 10.1.1.99

Config register settings: Specifies what the router will do when it boots.

Router(config)#config-register 0x2102

Create a sub logical interface under the physical interface.

Enable 802.1q trunking on the interface.

Set IP address.

Router(config)#int fa0/0.1

Router(config-subif)#encapsulation dot1Q 1

Router(config-subif)#ip address 10.1.1.1

255.255.255.0

Enable OSPF on any local interface starting with IP address 10.1.xx

Router(config-)#router ospf 1

Router(config-router)#network 10.1.0.0

0.0.255.255 area 0

EIGRP can be configured the same as RIP or using the mask option.

Router(config)#router eigrp 1

Router(config-router)#network 172.16.0.0 Or

Router(config-router)#network 172.16.2.0

0.0.0.255

Set the ACL standard. This standard uses numbers from 1 to 99.

Router(config)#access-list 1 permit

172.16.1.1

Set up Extended ACL. The first address is the source IP address.

Router(config)#access-list 101 deny tcp host

172.16.1.1 host 172.16.2.1 eq telnet Router(config)#access-list 101 permit ip any any

Use the group command to attach an ACL to an interface: Use the group command to attach an ACL to an interface.

Router(config)#interface fa0/0

Router(config-if)#ip access-group 1 out

Example of using ACL names instead of numbers.

Router(config)#ip access-list extended my_list

Router(config-ext-nacl)# deny tcp host

172.16.1.1 host 172.16.2.1 eq ftp

Router(config-ext-nacl)# permit ip any any

Assign ACL to interface by name.

Router(config)#int fa0/0

Router(config-if)#ip access-group my_list in

Configuring a static NAT to allow a server to be access via the Internet, using the IP address on interface s0/0/1: Configuring a static NAT to allow a server to be access via the Internet, using the IP address on interface s0/0/1.

Router(config)#ip nat inside source static

10.1.1.2 interface s0/0/1

Defining interface which NAT takes place between: Defines the interface which NAT takes place between.

Router(config)#int fa0/0.1

Router(config-if)#ip nat inside

Enables RIPng: Enables RIPng

Router(config)#ipv6 unicast-routing

Router(config)#ipv6 router rip ccna

Router(config)#int s0/0/0

Router(config-if)#ipv6 rip ccna enable

Describe

Command

Enable automatic setup dialog when device starts without configuration.

Switch#setup

Displays the config held in DRAM. Which is lost if not copy run start command is not used: Displays the config held in DRAM. Which is lost if not copy run start command is not used.

Switch#show running-config

Displays the NVRAM (None volatile) config: Displays the NVRAM configuration.

Switch#show startup-config

Saves the config: Saves the configuration, without this command all changes, configuration will be lost.

Switch#copy running-config startup-config

Saves the running config to a TFTP server: Saves the running config to a TFTP server.

Switch#copy running-config tftp

Copy IOS files to a TFTP server: Copy IOS files to a TFTP server.

Switch#copy flash tftp

Copies files from a TFTP server to the device flash: Copy files from TFTP server to the device flash.

Switch#copy tftp flash

Erase the config held in NVRAM: Erase the configuration held in VNRAM. If this command is executed with reload, all configuration will be lost.

Switch#erase startup-config

Reboots the device: Reboots the switch.

Switch#reload

Abort sequence: Cancel a command, procedure

6

Suspend Telnet Session: Suspend the telnet session

Press 6 at the same time, release all keys and immediately press x

Show the current sessions: View the current sessions, any session with * is the active session.

Switch#show sessions

Forcible closes a telnet session: Force closes a telnet session.

Switch#disconnect

Set the device local clock: Set the local time for the device. This command is not available in configuration mode.

Switch#clock set 10:00:00 April 2 2008

Display the IOS version along with other useful info: View the IOS version and other useful information such as system uptime, register configuration...

Switch#show version

View flash file contents.

Switch#show flash

Watch the time.

Switch#show clock

View currently logged in users.

Switch#show users

By default displays the last 10 commands: View the last 10 commands used.

Switch#show history

Displays the ARP cache: View the ARP cache.

Switch#show arp

Displays the spanning tree status on vlan 1: Views the spanning tree status on vlan 1.

Switch#show spanning-tree vlan 1

Lists all the configured vlans: Lists all the configured vlans.

Switch#show vlan

Displays VTP info such as VTP mode, VTP domain, VTP counter: Displays VTP info such as VTP mode, VTP domain, VTP counter.

Switch#sh vtp status

Ping selected address: Ping an IP address.

Switch#ping 10.1.1.1

Extended ping: Must be performed in privilege mode.

Switch#ping

Display the interface status: Display the interface status.

Switch#show int fa0/1

Displays the vlan status and the IP address VLAN 1 (often the management vlan): View VLAN 1 status.

Switch#show interfaces vlan 1

Displays a list of CDP neighbors: View a list of CDP neighbors.

Switch#show cdp neighbors

Extended information on the above: View more information than the above command.

Switch#show cdp neighbors details

Display CDP packets as they arrive: View CDP packets as they arrive.

Switch#debug cdp packets

Display ping packets as they arrive: Display ping packets as they arrive.

Switch#debug icmp packets

Display switch MAC Addresses table. These entries are learned from the source mac address in the Ethernet frames:

Switch#show mac address-table

Request

Cisco Commands

Enter privileged mode

enable

Return to user mode from privileged

disable

Log out of the router

logout/exit/quit

View router version

Router#show version

View current configuration (DRAM)

Router#show running-config

View startup configuration (NVRAM)

Router#show startup-config

View IOS, flash file size

Router#show flash

View all recorded router logs.

Router#show log

View interface status of interface e0

Router#show interface e0

Displays the interface operational status and IP addresses for all router interfaces: Views the interface operational status and IP addresses for all router interfaces.

Router#show ip interface brief

View cable type on s0

Router#show controllers 0

View connected cdp devices

Router#show cdp neighbor

View details on all devices

Router#show cdp entry *

Displays all the configured routing protocols: View all the configured routing protocols.

Router#show ip protocols

Displays the IP routing table: Displays the IP routing table.

Router#show ip route

Show access list

Router#show access-lists

See which router can see the ISDN switch

Router#show isdn status

Displays the NAT translations: View the NET translations.

Router#show ip nat translations

View physical cable configuration:

DTE/DCE, x.21, V.35,

RS232

Router#show controllers s 0

Displays the end-to-end status: Displays the end-to-end status

Router#show frame-relay pvc

Displays the type of LMI and the number LMI frames: Displays the type of LMI and the number LMI frames.

Router#show frame-relay lmi

Displays the frame relay inverse ARP table: Displays the frame relay inverse ARP table.

Router#show frame-relay map

View ospf neighbor list and their status

Router#show ip ospf neighbor

View ospf interface status.

Router#show ip ospf interface

View eigrp neighbor list and their status.

Router#show ip eigrp neighbor

View EIGRP interface status.

Router#show ip eigrp interface

View all trunk ports on the device

Router#show interface trunk

ping IPv6

Router#ping 2000:1000:500:3::1

debug all