Lost Internet Connection Upgrading Ubuntu 20.04.6: Two Different Interfaces named eno1 eth1
While upgrading Ubuntu from 16.x to 18.x, and eventually to 20.x, you might encounter a situation where you lose your internet connection. This problem may be caused by two different network interfaces showing up after the upgrade, which could be named something like eno1 and eth1. This article will explain the possible reasons for this issue and provide some solutions.
Understanding the Issue
After the upgrade, it is possible to see two separate network interfaces in your system. Usually, these interfaces are named eno1 and eth1, or other similar names depending on your hardware. Commonly, these represent the same physical network card but are seen as separate interfaces at the software level.
Reasons for Multiple Interfaces
This issue might occur due to the upgrade process or a specific configuration in the system. The Linux kernel may create separate interfaces for network cards that support multiple MAC addresses. This feature, called bonding, is a method used to combine multiple network interfaces into a single bonded interface.
Identifying the Interfaces
To identify the interfaces and investigate the issue, you can utilize the lshw command, which shows an overall summary of your hardware. Run the following command in your terminal:
sudo lshw -class network
In the output, look for the interfaces listed and identify their respective drivers and device descriptions.
Solution: Disabling Bonding
If the issue stems from the Linux kernel creating multiple bonded interfaces, it can be solved by disabling bonding configurations. To do this, you will need to edit a few files:
Step 1: Disable Bonding in /etc/network/interfaces
Open the /etc/network/interfaces file by using one of the following commands:
sudo nano /etc/network/interfaces
sudo vi /etc/network/interfaces
Comment out or remove any existing bonding-related configuration and save the file.
Step 2: Comment Out Bonding Configuration in /etc/netplan
Next, open the /etc/netplan/*.yaml file:
sudo nano /etc/netplan/*.yaml
Look for bonding configurations in the file and comment them out by adding a '#' symbol at the beginning of the line. Save the file after editing.
Step 3: Apply the Changes
After you have made necessary changes, use the following commands to apply them:
sudo netplan generate
sudo netplan apply
Solution: Manually Set IP Address
If the issue is not caused by bonding, you may try to manually set the IP addr