10 Cisco Switch Configuration Best Practices

Cisco switches are one of the most popular networking devices on the market. They are used in a variety of networking environments, from small home networks to large enterprise networks.

Cisco switches are highly configurable and offer a wide range of features. However, configuring Cisco switches can be a complex and time-consuming task. In this article, we will discuss 10 Cisco switch configuration best practices that you should follow to make your life easier.

1. Configure the switch hostname

The hostname is used to identify the switch in different network management protocols such as Simple Network Management Protocol (SNMP). If you don’t configure the hostname, the switch will use its default name, which is usually the model number of the switch. This can make it difficult to manage multiple switches because you have to remember the model numbers of each switch.

It’s also a good idea to use a consistent naming scheme for all your devices. For example, you could use the location of the device followed by the type of device. So, a switch in the New York office would be named “ny-switch1”. This makes it easy to identify the device when you’re looking at logs or other data.

Finally, the hostname is used in some security features such as AAA (Authentication, Authorization, and Accounting). If you don’t configure the hostname, these features will not work properly.

2. Assign an IP address to the management interface

The management interface is the only way you can remotely access and manage the switch. If it doesn’t have an IP address, you won’t be able to connect to it over the network.

Not only that, but the management interface is also used for things like downloading software updates and backups. So if it doesn’t have an IP address, you won’t be able to take advantage of these features either.

Bottom line: Always assign an IP address to the management interface on your Cisco switches!

3. Enable SSH access and disable Telnet access

Telnet is an unencrypted protocol, which means that all data sent over a Telnet connection, including passwords, can be intercepted and read by anyone on the network. SSH, on the other hand, is an encrypted protocol, so data sent over an SSH connection is much more secure.

Therefore, it’s important to enable SSH access and disable Telnet access on your Cisco switches, in order to protect the data passing through them. You can do this by using the following commands:

Switch(config)#ip ssh version 2
Switch(config)#line vty 0 4
Switch(config-line)#transport input ssh
Switch(config-line)#exit

4. Create a local user account for login authentication

If an attacker were to gain access to your switch, they would then have access to all of the devices on that switch. By creating a local user account, you can limit the attacker’s access to only the switch itself, and not the devices connected to it.

Creating a local user account is a two-step process. The first step is to create the user account itself, and the second step is to assign the user account to a privilege level.

The privilege level will determine what the user can and cannot do on the switch. For example, a user with privilege level 1 will only be able to view the switch’s configuration, while a user with privilege level 15 will be able to modify the switch’s configuration.

It’s important to note that you should never use the default username and password when configuring a Cisco switch. Doing so would leave your switch vulnerable to attack.

5. Disable CDP globally or on specific interfaces

CDP (Cisco Discovery Protocol) is a Layer 2 protocol that runs over all active physical interfaces on a Cisco device. By default, CDP is enabled on all interfaces and sends periodic updates about the local device to neighboring devices also running CDP.

The problem with CDP is that it can be used by attackers to gather information about your network. For example, an attacker could use CDP to determine which type of Cisco device they are dealing with, what software version it is running, and what other devices are connected to it.

Therefore, it is important to disable CDP globally or on specific interfaces that do not need it. You can do this with the following command:

no cdp run

6. Change the default privilege level of the console port

The console port is used to access the switch’s command line interface (CLI). By default, the privilege level of the console port is set to 15, which gives users full access to all commands. However, if an unauthorized user were to gain access to the console port, they would have complete control over the switch.

To prevent this, you should change the default privilege level of the console port to 1. This will restrict users to a limited set of commands, making it more difficult for an attacker to gain control of the switch.

Additionally, you should also consider changing the password for the console port. The default password is “cisco”, which is well-known and easy to guess. By changing the password to something more secure, you can further protect the switch from unauthorized access.

7. Set up logging

Logging allows you to track activity on your switch and see who is doing what. This is important for security and troubleshooting purposes. Without logging, it would be very difficult to track down someone who was trying to break into your network, or to figure out why your switch keeps crashing.

To set up logging, you need to first enable it on the switch. You can do this with the “logging” command. Once logging is enabled, you need to specify a syslog server. This is the computer that will receive the log messages from the switch.

You can use a free syslog server like Kiwi Syslog Daemon, or you can use a commercial one like SolarWinds Log & Event Manager.

Once you have logging set up, you can use the “show log” command to view the logs. You can also use the “debug” command to view detailed information about what is happening on the switch.

8. Configure SNMP

SNMP allows you to manage your Cisco switch remotely, which is essential for network management. It also allows you to monitor your switch for errors, so you can be proactive about solving problems.

Configuring SNMP on your Cisco switch is not difficult, but it’s important to do it correctly. Be sure to use a strong community string and restrict access to only the IP addresses that need it.

9. Configure NTP

NTP ensures that all of your devices have the same, accurate time. This is important for a number of reasons. For one, it makes troubleshooting easier. If you see an issue and check the timestamps on your logs, you’ll be able to more easily identify which events happened before or after the issue occurred.

It’s also important for security. Many security features, like intrusion detection and prevention systems, rely on accurate timestamps. If your devices don’t have the same time, it can lead to false positives or negatives.

Finally, it’s just good practice. When you’re configuring any network device, it’s always a good idea to configure NTP. That way, you can be sure that all of your devices are synchronized and you won’t have any issues down the road.

10. Configure Port Security

Port security is a switch feature that can be used to restrict access to a switch port based on MAC addresses. By default, a switch port can have up to 1,024 MAC addresses learned on it. When port security is configured on a switch port, the number of MAC addresses that can be learned on that port is reduced.

If the number of MAC addresses learned on a port exceeds the port’s maximum allowed MAC addresses, the port will shut down. This prevents unauthorized devices from accessing the network through that port.

Port security can be configured manually or through the use of DHCP snooping and IP source guard.