Good evening, my network engineer friends.

As the core device connecting various nodes, the stability and reliability of switches directly affect the health of the entire network system. Routers and switches are also the two things we network engineers must interact with daily. Maintenance and inspection are essential tasks for many novice network engineers. However, to do a good job, the experience of senior engineers is very important. After all, they are “senior” network engineers, and they have their own little tricks. For example, switches have high requirements for room temperature and environment, there are some techniques for software and hardware maintenance, and preventive maintenance should be consciously conducted. Many people do not have these taught to them and need to explore them in their work.

However, these techniques and methods are mostly derived from theoretical foundations. Mastering the core, you naturally won’t be afraid of troubleshooting and handling issues. So today, let’s talk about the precautions for maintaining switches. After reading this article, daily maintenance can be easily resolved.

Daily Maintenance of Switches

1 What Senior Network Engineers Have to Say

Regarding basic network maintenance, you need to be familiar with the configuration of major brands’ switches, routers, firewalls, and other hardware devices, and have the ability to build small local area networks. As well as basic capabilities for computers, printers, IP configuration, etc. These are the basics of the basics and must be mastered.

When a workstation is connected to several ports of a switch, it cannot ping other computers on the LAN, but the “Local Area Connection” icon on the desktop still shows the network is connected. This situation has occurred many times. After investigation, it was found that due to the different configurations of various switches, new engineers often make configuration errors when configuring switches.

So, I always advise them:

First, check if the computers being pinged have firewalls installed. Layer 3 switches can set VLANs (Virtual Local Area Networks). Workstations in different VLANs cannot ping each other without setting up routing. Therefore, modify the VLAN settings to place them in the same VLAN or set up routing to allow communication between VLANs.

If you cannot ensure the user’s configuration is correct, restore the default configuration first, and then configure step by step.

2 Switch Maintenance Basics

01 Hardware Maintenance

In the process of maintaining switches, both hardware and software maintenance are indispensable components. For hardware maintenance, regular cleaning of the switch’s exterior and fans is very important, which helps avoid overheating or hardware damage caused by dust accumulation.

Additionally, ensure the switch is placed in a suitable environment, avoiding high humidity or high temperatures, which can affect its normal operation. Physical inspections are also essential, including regular checks of power modules, fans, ports, etc. If any problematic components are found, they should be replaced promptly.

02 Software Maintenance

Software maintenance is equally important. Regularly updating the switch’s firmware can improve system stability and security, as well as gain new features and performance improvements.

To prevent data loss or issues caused by configuration errors, regularly back up the switch’s configuration files. Additionally, installing necessary security patches is crucial to protect the system from known vulnerabilities.

03 Daily Monitoring

In addition to hardware and software maintenance, daily monitoring is also an indispensable part of maintaining switches. By using network monitoring tools, you can regularly check the switch’s performance indicators, such as CPU utilization, memory usage, port throughput, etc., which helps identify potential issues in a timely manner.

At the same time, enabling log recording to track system events and anomalies is a good habit for subsequent analysis and troubleshooting. Configuring threshold alerts is also a good practice. When performance indicators exceed the normal range, notifications can be automatically triggered to take timely measures.

3 Key Points of Daily Maintenance

01 Performance Optimization

Performance optimization can be achieved in various ways. Plan network traffic reasonably to avoid congestion and ensure the priority of critical applications and services. Configure Quality of Service (QoS) according to business needs to optimize bandwidth allocation. Implement redundancy design, such as multi-path load balancing, backup routing, etc., to improve network reliability and availability.

02 Security Considerations

Security considerations are another important aspect of maintenance work. Restrict physical and logical access to switches, allowing only authorized personnel to manage them. Adopt strong password policies and regularly change passwords to enhance security.

Enable encryption protocols to ensure data transmission security. Use the Console interface for local management and configuration, ensuring management reliability and security. When using Telnet for remote access to switches, ensure appropriate security measures are in place, such as strong passwords and access control lists.

Using the SSH method provides a more secure remote access method because it is encrypted, effectively preventing man-in-the-middle attacks.

03 Console Method

How to log in to the switch’s console port using HyperTerminal? When logging in to the console port, prepare a cable connecting the console port and RS232 port in the switch.

Connect the cable, click “OK,” and select COM1 or COM3 during the connection.

After selecting COM1, click “OK,” click “Restore Defaults,” and set up HyperTerminal. After clicking “OK,” HyperTerminal is set up, and you can enter the switch by pressing Enter.

04 Telnet Method

By configuring the switch accordingly, you can use a username + password method. You can set levels. If not set, the default level is 1, which only allows login but not system view access.

If the user level is not set when configuring users or passwords, the default level is 1. To manage the switch, relevant configuration settings are needed.

05 Using SSH

When logging in to the switch, the password is encrypted. If using the Telnet method, the password is in plain text.

However, the switch only supports the SSH server side, not the SSH client side.

You cannot use the SSH method to log in to the switch first and then SSH to other switches from it.

Then use the SecureCRT software to SSH login. Set the hostname, which is the switch’s management IP address, the username as configured admin, select SSH1 for the protocol, and click OK.