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Just like riding a bicycle, nobody's born knowing how to setup a network switch. And this process is a little more advanced than, say, setting up your home Internet or even a plug-and-play type switch. But, with the right guidance, a can-do attitude, and a dash of bravery, even newbie IT professionals can integrate a new Cisco switch into their business environment. As your virtual training wheels, we've broken down the task into its simplest parts so you can successfully create client VLANS, build DHCP systems, and assign access ports without skinning your knees.
Check the model number of your shiny new switch. Or, if you are using a spare, check the device hardware and its connected cables for any damages. If everything checks out, power on the switch and verify that all the indicator lights are in working order. Next, use a rollover cable to console into the switch from your computer. To do this, you will need to download and install Putty (or a similar, fun-named software tool). Run Putty and select the 9600 speed serial connection. You are now connected to the switch and ready to check the output of the following commands:
For spare switches, make sure to delete the flash:vlan.dat file to erase the previous configuration.
Unlike with that punny name you gave your home Wi-Fi network, when setting up the hostname for your switch you should probably stick to a more professional and standard naming convention. Follow any preset naming assignment your company is using and then assign an IP address on the management VLAN. Next, make sure your switch has a set hostname and domain name:
Hit the show vtp status command to reveal your Virtual Trunking Protocol (VTP) revision numbers. The VTP revision numbers determine which updates are to be used in a VTP domain. When you set a VTP domain name, the revision number is set to zero—after which each change to the VLAN database increases the revision number by one. Your switch will only process data from a neighboring switch coming from the same domain and if the revision number of the neighboring switch is higher than its own. This means that the switches will update their VLAN configuration based on the VTP information being sent by the switch with the highest revision number.
So, before you add your switch to the network, you’re going to want to set its revision number to zero. To easily reset the domain back to zero, change the config mode to transparent:
You might already have a template ready for access port configuration, but in case you don’t, here are some commands you should use:
Enter the command sh int g0/1 capabilities and check the trunking protocol supported. If ISL is supported, you have to issue the switchport trunk encapsulation dot1q on the trunk port configuration. If not, simply type switchport mode trunk. It means there is no other encapsulation supported so there is no need for an encapsulation command. It only supports 802.1Q.
After already performing basic network switch configurations, it’s time to generate RSA keys to be used during the SSH process, using the crypto commands shown here:
Choose the size of the key modulus in the range of 360 to 2048 for your General Purpose Keys. Choosing a key modulus greater than 512 may take a few minutes.
If you have not set the console line yet, you can easily input these values:
Set the enable password using the enable secret password command. Then, set the privilege exec password with username name privilege 15 secret password. Make sure that the password-encryption service is activated.
Verify SSH access by typing ‘sh ip ssh’ to confirm that the SSH is enabled. You can now try to log in from a remote machine to verify that you can ssh to your Cisco switch.
You’ve made it through the learning process with (hopefully) minimum bumps and bruises, and you’re just about ready to ride off. All that’s left is to test your access, reload the switch, and ready the cables. Once that’s done, label your switch, rack it up, and go enjoy doing anything that doesn’t involve switch configuration!
If you'd like further assistance, or have more devices to configure, please visit our small business community. There you'll find answers to common questions and connect with people running similar businesses and facing similar IT challenges.
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