Network failures have become more complex nowadays!

If a computer terminal in the office cannot access the internet, can we simply conclude that the issue lies with the computer’s network cable?

No, we cannot immediately assume it’s a problem with the network cable.

Why Not?

With increased emphasis on network security and the implementation of various network strategies, network failures can arise from multiple causes.

How Do We Troubleshoot Network Failures?

Traditionally, the approach was to first check for hardware issues and then look into software factors. However, now we need to reverse this order: we should first investigate software reasons and then hardware reasons. Specifically, we start with the following factors:

1. Check the Network Adapter Settings on the Computer: Ensure that the IP address, gateway, and DNS are correctly configured.
2. Examine the Configuration of the Directly Connected Switch: Depending on the network environment, different interfaces may be configured as access or trunk modes. Different interfaces may be added to different VLANs to grant different permissions. This is why the network works fine before changing an interface but fails afterward.
3. Check for Unused Ports in the Switch: For security reasons, unused ports in the switch may be shut down, causing the status light to not turn on when a network cable is plugged into these ports.
4. Review Network Security Settings: Some network security devices may block certain IP addresses from accessing the internet, leading to a situation where the computer’s network adapter status is normal but it cannot access the internet.
5. Software Reasons: These are the main software reasons. If you have different insights, feel free to add them.
6. Hardware Factors: After ruling out software reasons, the main hardware factors include network card failure, network cable connector (RJ45) failure, network cable failure, switch port failure, and poor contact between network modules and RJ45 connectors. Feel free to add more.