Switching VLAN STP VTP DTP Ether Channels

Basic Switch configurations commands

In this article I will introduce the Cisco Internetwork Operating System (IOS) command line interface (CLI) for the 2960 series switch. You will need to logon to a switch and become familiar with the different levels of access on the switch. You will also become familiar with the commands available to you in each mode (user or privileged) and the switch help facility, history, and editing features.

User vs. Privileged Mode

User mode is indicated with the > next to the switch name. You can look at settings but can not make changes from user mode. In Privilege mode, indicated by the #, you can do anything. To get into privilege mode the keyword is enable.

HELP

To view all commands available from this mode type:?This will give you the list of all available commands for the switch in your current mode. You can also use the question mark after you have started typing a command. For example if you want to use a show command but you do not remember which one it is, use the ? as this will output all commands that you can use with the show command.

Configuration Mode

From privilege mode you can enter configuration mode by typing config term command you can exit configuration mode type type end or <CTL>+z

Configuration of Cisco 2960 Switch

To practically implement these command either create a simple topology on packet tracer or download this topology.

Ddownload Topology
basic switch configuration

Now click on any switch and configure it as given below

To know all available command on user exec mode type ? and press enter

Switch>?
Exec commands:
    [1-99]         Session number to resume
    connect        Open a terminal connection
    disconnect     Disconnect an existing network connection
    enable         Turn on privileged commands
    exit           Exit from the EXEC
    logout         Exit from the EXEC
    ping           Send echo messages

[Output is omitted]

Three command can be used to logout from terminal.

Switch>enable
Switch#disable
Switch>exit

Switch con0 is now available

Press RETURN to get started.

show version Command will display the device platform, detected interface, ios name

Switch>enable
Switch#show version
Cisco IOS Software, C2960 Software (C2960-LANBASE-M), Version
12.2(25)FX, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2005 by Cisco Systems, Inc.
Compiled Wed 12-Oct-05 22:05 by pt_team
ROM: C2960 Boot Loader (C2960-HBOOT-M) Version 12.2(25r)FX,
RELEASE SOFTWARE (fc4)
System returned to ROM by power-on
Cisco WS-C2960-24TT (RC32300) processor (revision C0) with
21039K bytes of memory.
24 FastEthernet/IEEE 802.3 interface(s)
2 Gigabit Ethernet/IEEE 802.3 interface(s)

[Output is omitted]

show mac address Command will show all detected mac address dynamically and manually

Switch#show mac-address-table
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----

   1    0001.643a.5501    DYNAMIC     Gig1/1

To view run time configuration of RAM use show running-config command

Switch#show running-config
Building configuration...
Current configuration : 925 bytes
version 12.2
no service password-encryption
!
hostname Switch

[Output is omitted]

To view startup configuration [ Stored in NVRAM] use show startup-config command

Switch#show startup-config
Current configuration : 925 bytes
version 12.2
no service password-encryption
!
hostname Switch

[Output is omitted]

To get information about VLAN configuration use show vlan command

Switch#show vlan

VLAN Name                      Status    Ports
---- -------------------------------- --------- -----------------------
1    default                   active    Fa0/1, Fa0/2, Fa0/3, Fa0/4
                                         Fa0/5, Fa0/6, Fa0/7, Fa0/8
                                         Fa0/9, Fa0/10, Fa0/11, Fa0/12
                                         Fa0/13, Fa0/14, Fa0/15, Fa0/16
                                         Fa0/17, Fa0/18, Fa0/19, Fa0/20
                                         Fa0/21, Fa0/22, Fa0/23, Fa0/24
[Output is omitted]

show interface command will show all detected interface with their hardware description and configuration

Switch#show interfaces
FastEthernet0/1 is up, line protocol is up (connected)
  Hardware is Lance, address is 0060.2f9d.9101 (bia 0060.2f9d.9101)
  MTU 1500 bytes, BW 100000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
[Output is omitted]

interface vlan 1 is used to assign ip address and default gateway to switch. Show interface vlan 1 will give a over view of vlan1.

Switch#show interface vlan1
Vlan1 is administratively down, line protocol is down
  Hardware is CPU Interface, address is 0060.5c23.82ae
   (bia 0060.5c23.82ae)
  MTU 1500 bytes, BW 100000 Kbit, DLY 1000000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  ARP type: ARPA, ARP Timeout 04:00:00

[Output is omitted]

delete command is used to delete all vlan configuration from switch Don’t add space between flash and vlan.dat Run this exactly shown here adding a space could erase flash entirely leaving switch blank

Switch#delete flash:vlan.dat
Delete filename [vlan.dat]?
Delete flash:/vlan.dat? [confirm]
%deleting flash:/vlan.dat

Startup configuration can be removed by erase commands

Switch#erase startup-config
Erasing the nvram filesystem will remove all configuration files!
Continue? [confirm]
[OK]
Erase of nvram: complete
%SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram

Basic Switch Configuration Step by Step

use configure terminal command to go in global configuration mode

Switch#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.

Now change default switch name to switch 1

Switch(config)#hostname Switch1

Set enable password to vinita and secret to nikki

Switch1(config)#enable password vinita
Switch1(config)#enable secret nikki

Set console password to vinita and enable it by login command. Order of command is important. Set password before you enable it.

Switch1(config)#line console 0
Switch1(config-line)#password vinita
Switch1(config-line)#login
Switch1(config-line)#exit

Enable 5 telnet session [ vty0 - vty4] for router and set their password to vinita

Switch1(config)#line vty 0 4
Switch1(config-line)#password vinita
Switch1(config-line)#login
Switch1(config-line)#exit

Now set switch ip address to 192.168.0.10 255.255.255.0 and default gateway to 192.168.0.5

Switch1(config)#interface vlan1
Switch1(config-if)#ip address 192.168.0.10 255.255.255.0
Switch1(config-if)#exit
Switch1(config)#ip default-gateway 192.168.0.5

Set a description finance VLAN to interface fast Ethernet 1

Switch1(config)#interface fastEthernet 0/1
Switch1(config-if)#description finance VLAN

By default switch automatically negotiate speed and duplex but you can adjust it manually

Switch1(config-if)#duplex full
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to down
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1,
 changed state to downSwitch1
(config-if)#duplex auto
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
Switch1(config-if)#duplex half
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to down
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1,
changed state to down
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
Switch1(config-if)#duplex auto
Switch1(config-if)#speed 10
Switch1(config-if)#speed 100
Switch1(config-if)#speed auto
Switch1(config-if)#exit
Switch1(config)#exit

mac address table can be wiped out by clear commands

Switch1#show
Switch1#show mac-address-table
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----

   1    0001.643a.5501    DYNAMIC     Gig1/1
Switch1#clear mac-address-table
Switch1#clear mac-address-table ?
  dynamic  dynamic entry type
Switch1#clear mac-address-table dynamic

To restart switch use reload command [ running configuration will be erased so copy it first to startup configuration ]

Switch1#reload
Proceed with reload? [confirm]
Switch con0 is now available
Press RETURN to get started.

CCNA basic switch configuration commands sheet

Command descriptions
switch>?

The ? works here the same as in a router Used to get the list of all available commands

switch>enable

User mode, same as a router

switch#

Privileged mode

switch#disable

Leaves privileged mode

switch>exit

Leaves user mode

switch#show version

Displays information about software and hardware.

switch#show flash:

Displays information about flash memory (will work only for the 2900/2950 series).

switch#show mac-address-table

Displays the current MAC address forwarding table

.
switch#show running-config

Displays the current configuration in DRAM.

switch#show startup-config

Displays the current configuration in NVRAM.

switch#show vlan

Displays the current VLAN configuration.

switch#show interfaces

Displays the interface configuration and status of line: up/up, up/down, admin down.

switch#show interface vlan1

Displays setting of virtual interface VLAN 1, the default VLAN on the switch.

To Reset Switch Configuration
Switch#delete flash:vlan.dat

Removes the VLAN database from flash memory.

Delete filename [vlan.dat]?

Press Enter

Delete flash:vlan.dat? [confirm]

Press Enter

Switch#erase startup-config

Erases the file from NVRAM.

Switch#reload

Restarts the switch.

To Set Host Names
Switch#configure terminal

Moves to global configuration mode

Switch(config)#hostname Switch1

Creates a locally significant host name of the switch. This is the same command as the router.

Switch1(config)#
To Set Passwords
Switch(config)#enable password vinita

Sets the enable password to vinita

Switch(config)#enable secret nikki

Sets the encrypted secret password to nikki

Switch(config)#line console 0

Enters line console mode

Switch(config-line)#login

Enables password checking

Switch(config-line)#password vinita

Sets the password to vinita

Switch(config-line)#exit

Exits line console mode

Switch(config-line)#line vty 0 4

Enters line vty mode for all five virtual ports

Switch(config-line)#login

Enables password checking

Switch(config-line)#password vinita

Sets the password to vinita

Switch(config-line)#exit

Exits line vty mode

Switch(config)#
To Set IP Addresses and Default Gateways
Switch(config)#interface vlan1

Enters the virtual interface for VLAN 1, the default VLAN on the switch

Switch(config-if)#ip address 192.168.0.10 255.255.255.0

Sets the IP address and netmask to allow for remote access to the switch

Switch(config-if)#exit
Switch(config)#ip default-gateway 192.168.0.5

Allows IP information an exit past the local network

To Set Interface Descriptions
Switch(config)#interface fastethernet 0/1

Enters interface configuration mode

Switch(config-if)#description Finance VLAN

Adds a description of the interface

To Set Duplex Operation
Switch(config)#interface fastethernet 0/1

Moves to interface configuration mode

Switch(config-if)#duplex full

Forces full-duplex operation

Switch(config-if)#duplex auto

Enables auto-duplex config

Switch(config-if)#duplex half

Forces half-duplex operation

To Set Operation Speed
Switch(config)#interface fastethernet 0/1
Switch(config-if)#speed 10

Forces 10-Mbps operation

Switch(config-if)#speed 100

Forces 100-Mbps operation

Switch(config-if)#speed auto

Enables autospeed configuration

MAC Address Table
switch#show mac address-table

Displays current MAC address forwarding table

switch#clear mac address-table

Deletes all entries from current MAC address forwarding table

switch#clear mac address-table dynamic

Deletes only dynamic entries from table

Written by Sanjay Kumar

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