Set up a Cisco switch

This entry shows the step I took to set up a Cisco switch at work

Basic Switch Setup

How to set up Cisco switches

Important Commands

Security

Lock down Cisco switch port to increase security

 

 

To assign an IP to a VLAN

Switch(config)#int vlan 1
Switch(config-if)#ip address 10.60.1.1 255.255.248.0
Switch(config-if)#no shut
Switch(config-if)#end

Select multiple ports to configure

Switch1#enable

Switch1(config)#interface range gigabitEthernet 0/1 – 20

Switch1(config-if-range)#spanning-tree portfast

Switch1(config-if-range)#switchport mode trunk

Switch1(config-if-range)#^Z

Switch1# copy running-configuration startup-configuration

Switch1#show running-configuration

How to configure VTP Client and Server?

VTP (VLAN Trunking Protocol) is the protocol that propagates the information about which VLANs exist from one switch to another switch. If VTP did not provide this information, VLANs would have to be created on all switches individually in the network.

VTP is a Cisco proprietary protocol. The default mode of a switch is configured as VTP server. In any case, the server services are turned off, use the following command to turn it back on as VTP server.

• SwitchA#vlan database
• SwitchA(vlan)#vtp server
• SwitchA(vlan)#exit

First create multiple VLANs with name, assign multiple ports to them then create 802.1q trunk link between the two switches to allow communication between VLANs.

To create a VLAN, first enter global configuration mode to run the following commands.

Configuration to create VLAN 2 and 3 on switch A (VTP server)

SwitchA(config)#configure terminal  (enter in global configuration mode)

SwitchA(config)#vlan 2(defining the vlan 2)

SwitchA(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchA(config)#vlan 3 (defining the vlan 3)

SwitchA(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchA(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 2)

SwitchA(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit(exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchA(config-if)#switchport access vlan 3(allot the membership of vlan 3)

SwitchA(config-if)#exit(exit from interface 4)

SwitchA(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 5)

Configuration of VTP client on switch B

SwitchB#vlan database

SwitchB(vlan)#vtp client

SwitchB(vlan)#vtp domain group1

SwitchB(vlan)#exit

Trunking with 802.1q

Now create 802.1q trunk link between the two switches to allow communication between VLANs.

On both switches, SwitchA and SwitchB type the following command with 802.1q at the fastethernet 0/1 interface.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchA(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchA(config-if)#end (exit from interface 1)

SwitchB(config)#interface fastethernet 0/1(select the Ethernet 0 of port 1)

SwitchB(config-if)#switchport mode trunk(set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchB(config-if)#end (exit from interface 1)

• To verify that fastethernet 0/1 has been established as trunk port, type the show interface fastethernet 0/1 switchport at the privileged EXEC mode.
• Although the VLAN definitions have migrated to the switch B using VTP, but it is necessary to assign ports to these VLANs on switch B.
• Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchB(config)#configure terminal

SwitchB(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 2)

SwitchB(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 4)

SwitchB(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 5)