Troubleshooting Ubuntu 18.04 Wired Network Issues: A Comprehensive Guide

Having trouble with your wired connection on Ubuntu 18.04? You're not alone. This guide walks you through common troubleshooting steps to identify and resolve issues with your Ethernet connection.

Understanding the Problem

The first step in troubleshooting any network issue is to understand what you're seeing. If your wired connection is not working on Ubuntu 18.04, you may encounter a variety of networking errors or simply be unable to access the internet via Ethernet. This guide will help you through the steps to get your connection back online.

Common Troubleshooting Steps

1. Check Physical Connections

A poor or loose Ethernet cable can cause connectivity issues. Ensure that the cable is securely connected to both your computer and the router or switch. Try using a different Ethernet cable or port on the router to rule out hardware issues.

2. Verify Network Settings

Ensure that your wired connection is enabled in the network settings. You can find these settings by navigating to Settings > Network and checking if the wired connection is turned on.

3. Check Network Manager

Open a terminal and run the following command to check the status of Network Manager:

bash
 systemctl status NetworkManager

If Network Manager is not running, you can start it with:

bash
sudo systemctl start NetworkManager

4. Release and Renew IP Address

In the terminal, run the following commands to release and renew the IP address:

bash
sudo dhclient -r
sudo dhclient

5. Check for Driver Issues

The network adapter might not have the correct driver installed. Check the output of the following command to see if a driver is loaded:

bash
lspci -nnk | grep -iA3 net

If a driver is missing, you may need to install it. Find the appropriate driver and install it using the package manager.

6. Check Firewall Settings

The firewall may be blocking the connection. You can check the status with:

bash
sudo ufw status

If the firewall is active, you can temporarily disable it for testing with:

bash
sudo ufw disable

7. Check Logs for Errors

Review your system logs for any network-related errors:

bash
dmesg | grep -i eth
journalctl -xe | grep NetworkManager

8. Update System

Ensure your system is up to date. Updates can fix bugs or issues that may be causing the problem:

bash
sudo apt update
sudo apt upgrade

9. Test with Live USB

Boot from a Live USB of Ubuntu 18.04 to see if the Ethernet works there. This test can help you determine if the issue is with your installation.

10. Reinstall Network Manager

As a last resort, you can try reinstalling Network Manager. If the problem persists, you may need to troubleshoot further:

bash
sudo apt remove --purge network-manager
sudo apt install network-manager

Conclusion

If none of these steps resolve the issue, check online forums or the Ubuntu community for further help. Providing specific details about your network adapter and any error messages can help others provide more effective assistance.