Cisco Switch Commands Cheat Sheet (CLI)

Cisco Switch Commands Cheat Sheet (CLI)

        Cisco switches can be used as plug-and-play devices out of the box but they also offer an enormous amount of features. Although the main purpose of the switch is to provide inter-connectivity in Layer 2 for the connected devices of the network, there are myriad features and functionalities that can be configured on Cisco Switches.

        In the following Cisco Switch Commands Cheat Sheet, I have tried to include the most important and frequently-used CLI commands that Cisco professionals encounter in real world networks. I know that the list is not exhaustive but I believe that the most useful commands are included. 

Verification Commands

01. TestSwitch#show version

[Displays software and hardware information]

 

02. TestSwitch#show running-config

[Displays currently running configuration in DRAM]

 

03. TestSwitch#show start                                           

[Displays configuration in NVRAM which will be loaded after reboot]

 

04. TestSwitch#show flash:

[Displays Flash memory information]

 

05. TestSwitch#show boot                                            

[Displays boot path and image]

 

06. TestSwitch#show clock                                          

[Displays the system clock]

 

07. TestSwitch#show interfaces                                  

[Displays all interfaces configuration and status of line]

 

08. TestSwitch#show vlan                                              

[Displays vlan number, name, status and ports associated with it]

 

09. TestSwitch#show vtp status                                  

[Displays VTP mode, Number of existing vlans and config revision]

 

10. TestSwitch#show interface status                          

[Displays interface status, vlan, Duplex, Speed and type]

 

11. TestSwitch#show etherchannel                            

[Displays etherchannel information]

 

12. TestSwitch#show cdp neighbors                            

[Displays information of connected devices]

 

13. TestSwitch#show cdp neighbors detail                

[Displays detailed information of connected devices]

 

14. TestSwitch#show mac address-table    

[Displays current MAC address forwarding table and which MAC is learned on each switch port]

 

15. TestSwitch#show spanning-tree                            

[Displays spanning-tree state information, which interfaces are in active or blocking state etc]

Resetting the Switch

 

01. TestSwitch#delete flash:vlan.dat                                

[Deletes vlan database from flash memory so you can start adding new VLANs from scratch]

 

02. TestSwitch#erase startup-config                            

[Delete start-up file from NVRAM]

 

03. TestSwitch#reload                                                    

[Reboot the Switch]

 

Setting Host Names

 

01. TestSwitch#configure tertminal                                                     

[Entering into Global Configuration Mode]

 

02. TestSwitch(config)#hostname MySwitch              

[Enter the hostname of the switch]

03. MySwitch(config)#

 

Setting login credentials

 

01. MySwitch(config)#username admin password csico1234  

[create username and password for logging in to the switch] 

 

02. MySwitch(config)#enable secret test1                                    

[Sets encrypted secret password using MD5 algorithm. This is the enable password that you will be asked to enter when trying to enter into “enable” mode]

 

03.MySwitch(config)#service password-encryption                  

[Encrypt all the passwords using MD5]

 

Console Access

 

01. MySwitch(config)#line con 0                                                      

[Enter into line console mode]

 

02. MySwitch(config-line)#password test3                                  

[Set password on console]

 

03. MySwitch(config-line)#login                                                      

[Enable password checking on console]

 

SSH/Telnet Access to the switch

 

01. MySwitch(config)#line vty 0 4     

[Enters line vty mode for all five virtual ports]

 

02. MySwitch(config-line)#transport input ssh                            

[Enable SSH]

 

03. MySwitch(config-line)#transport input telnet                        

[Enable telnet]

 

04. MySwitch(configiline)#password test3                                  

[Set password]

Setting IP Address 

(To allow remote access to the switch)

 

01. MySwitch(config)#interface vlan1                                          

[Enters vlan1, the native vlan]

 

02. MySwitch(config-if)#ip address 192.168.1.2 255.255.255.0

[Set IP address for management]

 

03. MySwitch(config-if)#exit

04. MySwitch(config)#ip default-gateway 192.168.1.1            

[Exit path for the switch – gateway IP]

 

Interface description

 

01. MySwitch(config)#interface g0/1

      MySwitch(config-if)#description TO SERVER

Duplex and Speed Settings

 

02. MySwitch(config)#interface g0/1

      MySwitch(config-if)#speed 10                                                

[Force 10Mbps Speed]

 

03. MySwitch(config-if)#speed 100                                              

[Force 100Mbps Speed]

 

04. MySwitch(config-if)#speed auto                                              

[Enable auto speed configuration]

 

05. MySwitch(config-if)#duplex auto                                          

[Enable auto duplex configuration on switch port]

 

06. MySwitch(config-if)#duplex full                                            

[Enable full duplex configuration on switch port]

 

07. MySwitch(config-if)#duplex half                                            

[Enable half duplex configuration on switch port]

 

Setting Web-based interface for configuration (GUI)

 

01. MySwitch(config)#ip http server                                            

[Enable HTTP server]

 

02. MySwitch(config)#ip http port 80  

[Set port number for HTTP]

 

Port-Security

 

01. MySwitch(config)#interface g0/1                                                     

[Enter the interface to set port-security]

02. MySwitch(config-if)#switchport port-security                                

[Enable port security on the interface]

03. MySwitch(config-if)#switchport port-security mac-address sticky

[Interface converts all MAC addresses to sticky secure addresses]

04. MySwitch(config-if)#switchport port-security maximum 1        

[Only one MAC address will be allowed for this port]

05. MySwitch(config-if)#switchport port-security violation shutdown

[Port will shut down if violation occurs]

06. MySwitch(config-if)#exit

07. MySwitch(config)#exit

08. MySwitch#show port-security                                                    

[Verifying Port security]

Save current configuration

01. MySwitch(config)# copy running-config startup-config

PortFast

        “Portfast” bypasses the Spanning Tree states and brings the port up as quickly as possible. Use it only if you connect a regular host (e.g Computer) on the port. Do not use this command when the port is trunk or if you connect other switches on the specific port.

02. MySwitch(config)# interface FastEthernet 0/1

03.MySwitch(config-if)# spanning-tree portfast

Configuring VLANs

01. MySwitch(config)#vlan 20                                                                      

[Create a Layer2 VLAN with id 20]

02. MySwitch(config-vlan)# name testvlan             

[Enter a name for the vlan]

03. MySwitch(config-vlan)#exit

04. MySwitch(config)#exit

05. MySwitch#show vlan brief                                                                      

[Verify the vlan database]

06. Assigning access ports to a vlan

07. MySwitch(config)#interface g0/1

08. MySwitch(config-if)#switchport mode access                                      

[Set the interface in switch access mode]

09. MySwitch(config-if)#switchport access vlan 20                                  

[Assign the port to vlan 20]

10. MySwitch(config-if)#exit

The following commands will select a range of interfaces (from 1 to 24) and add all of them to vlan20

11. MySwitch(config)#interface range gigabitEthernet 0/1-24

12. MySwitch(config-if)#switchport mode access                                    

13. MySwitch(config-if)#switchport access vlan 20                    

14. MySwitch(config-if)#exit

Configuring trunk port

01. MySwitch(config)#interface g0/2

02. MySwitch(config-if)#switchport trunk encapsulation dot1q            

[Configure the port to support 802.1Q Encapsulation (default is negotiate)]

03. MySwitch(config-if)#switchport mode trunk                                      

[Set the interface in permanent trunking mode]

04. MySwitch(config-if)#switchport trunk native vlan 20                        

[Specify native vlan for 802.1q trunks – OPTIONAL]

05. MySwitch(config-if)#switchport trunk allowed vlan 2-5                   

[vlans 2 to 5 are allowed to pass through the trunk]

06. MySwitch(config-if)#switchport trunk allowed vlan add 7    

[add also vlan 7 in the allowed vlans]

07. MySwitch(config-if)#switchport trunk allowed vlan remove 3  

[remove vlan 3 from the allowed vlans in the trunk]

08. MySwitch#show interface g0/2 trunk                                                    

[Verify the trunk ports and associated vlans on the specific interface]