Software & AppsOperating SystemLinux

Fixing Network Manager’s Default Route Issue

Ubuntu 9

In this article, we will delve into the issue of Network Manager not assigning a default route and discuss various solutions to fix this problem. This issue can be caused by a multitude of factors such as incorrect route configurations or missing gateway information.

Understanding the Issue

Before we dive into the solutions, it’s crucial to understand the issue at hand. The default route, also known as the gateway, is the path that network traffic will follow if no other route is specified for a given destination. This is typically set to be the router’s IP address. If Network Manager fails to set a default route, it can lead to connectivity problems, where you might be able to connect to your local network but not the internet.

Solution 1: Edit the Wireless Device NM Configuration File

The first solution involves editing the configuration file for your connection.

  1. Open the terminal and type the following command:
vim /etc/NetworkManager/system-connections/YOUR_WIFI_NAME

Here, vim is a text editor, and YOUR_WIFI_NAME should be replaced with the name of your wireless connection.

  1. Under the [ipv4] section, add the line never-default=false. This line ensures that this connection can be used as a default route.
  2. Save the file and exit the text editor.

Solution 2: Edit the NetworkManager.conf File

Another solution is to edit the NetworkManager.conf file.

  1. In the terminal, type:
vim /etc/NetworkManager/NetworkManager.conf
  1. Ensure that the line managed=true is present under the [ifupdown] section. If it is already set to true, try changing it to false. This line determines whether NetworkManager should manage network interfaces.
  2. Save the file and exit.

Solution 3: Restart Network Manager

After making the necessary changes, it’s important to restart the Network Manager service. This can be done using the following command:

service network-manager restart

Here, service is a command that runs a System V init script, network-manager is the name of the service, and restart tells the service to stop and then start again.

Solution 4: Check for Missing Gateway Information

The issue could also be due to missing gateway information. Here’s how to check and fix this:

  1. Use the nmcli command to edit the connection settings:
nmcli connection edit eth0

In this command, nmcli is a command-line client for NetworkManager, connection edit allows you to edit a connection’s settings, and eth0 is the name of the network interface.

  1. Check the current settings using the print command.
  2. Look for the ipv4.gateway field and ensure it is not empty. If it is missing, set the gateway using the set ipv4.gateway command followed by the gateway IP address.
  3. Save the changes using the save command.

Solution 5: Check DNS Settings

If you can ping IP addresses but not domain names, the issue might be with the DNS settings. Ensure that the DNS server is correctly configured. For instance, Google’s DNS server IP is

Other Considerations

If the issue persists, check for any recent updates or changes that may have caused the problem. It’s also a good idea to consult relevant forums or community discussions for specific distributions or devices for additional troubleshooting steps.

In conclusion, fixing the Network Manager’s default route issue involves checking and adjusting various settings. While it might seem complicated at first, with a bit of patience and understanding, it’s definitely something that can be resolved. Happy troubleshooting!

What is Network Manager?

Network Manager is a program that provides network configuration and management for Linux-based systems. It is responsible for managing network connections, including wired, wireless, and virtual connections.

How can I check if Network Manager is installed on my system?

You can check if Network Manager is installed on your system by running the command which NetworkManager in the terminal. If it is installed, the command will return the path to the Network Manager executable. If it is not installed, the command will not return any output.

Why is it important to have a default route set by Network Manager?

The default route, or gateway, is important because it determines the path that network traffic will follow if no other route is specified for a given destination. Without a default route, you may experience connectivity problems, where you can connect to your local network but not the internet.

Can I use a different text editor instead of Vim to edit the configuration files?

Yes, you can use a different text editor to edit the configuration files. Some popular alternatives to Vim are Nano, Emacs, and Sublime Text. Simply replace the vim command in the instructions with the command for your preferred text editor.

How do I restart the Network Manager service?

You can restart the Network Manager service by running the command sudo service network-manager restart in the terminal. The sudo command is used to run the command with administrative privileges, and network-manager is the name of the service.

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