Configuring Cisco 3560 switch

Let’s consider a scenario in which there are two several departments of the same company that have to be connected using logically separate networks (VLANs) and need to communicate with each other, while being connected on a single Layer 3 switch Cisco 3560.
The task is to organize the following subnets (VLANs):

• Sales department network (192.168.10.0 255.255.255.0)
• Accounting department network (192.168.20.0 255.255.255.0)
• IT administrators network (192.168.100.0 255.255.255.0)
• Network management subnet (192.168.1.0 255.255.255.0)

Step 0. Clear previous configuration

(This step should be performed only on new or test equipment, since it completely removes all existing configuration)
After you take your new switch out of the box, connect to it with a console cable and clear the factory configuration by entering the privileged mode and using the “write erase” command (you can learn more about Cisco IOS configuration modes in this article)

After this your switch will reboot, taking about three minutes to do so, and display a request for basic configuration wizard afterwards. You should decline:

Step 1. Hostname

Let’s call our switch SWR-DELTACONFIG-1 (SWR is an abbreviation from SWitch Router). To do this, enter the configuration mode (conf t) and type the following commands:

The hostname will change from “Switch” to the specified name.

Step 2. Configure remote access

In order to administer your switch remotely, you have to give it an IP address on VLAN 1. Don’t forget to switch on the interface by using the “no shutdown” command:

Step 3. Configure user authorization

In order for all users to be authorized and gain an access to the switch:

• Create a password for accessing the privileged mode (indicated by the “#” sign after the hostname) with the command “enable secret“
• Create a user account (and its password) for remote access with the command “username … secret …“

Turn on authorization using the local user and password database:

In order to check the availability of the privileged mode (#) after entering the above commands, exit all configuration modes by entering “exit” or “Ctrl+Z” until you are in the original “>” mode. After this try entering the privileged mode again using enable command and enter the password you specified above when asked.
If all commands were entered correctly, you should get something like this:

You can also check the remote access by entering “telnet 192.168.1.1” from the command line of a workstation. You should get a request for username and password in a telnet window.
After you’ve ensured that your switch is accessible via Telnet (TCP port 23), I recommend to secure your remote sessions by configuring SSH access (TCP port 22). Detailed instructions on how to do this are available in here.

Step 4. Create VLANs

Next, create a VLAN for each department and assign serial numbers and names to them:

Each switch has Vlan 1 as a default one. It will be used for remote control of the switch.
You can check the current VLAN configuration by issuing the “show vlan” command:

Make sure that all defined networks are in your list.

Step 5. Binding Vlans and ports

The next step is to create a correlation between a switch ports and VLANs. The switch we use for this example has 24 Gigabit Ethernet ports. Let’s split them as follows:

• 6 for administration network (Vlan 100)
• 12 for sales department (Vlan 10)
• 6 for accounting department (Vlan20)

It would be great to add description strings for each interface . This is a text field which doesn’t affect any other settings.

Then, ports will be shown next to each Vlan. The result of sh vlan command should be similar to this:

Step 6. Routing

In order for different VLANs to be able to communicate with each other, we need to create Layer 3 virtual interfaces for each VLAN: