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How To Fix “Error 101: Network is Unreachable” When Updating Ubuntu with APT

Ubuntu 8

In this article, we will explore how to fix the “Error 101: Network is Unreachable” issue when updating Ubuntu using the Advanced Package Tool (APT). This error is typically indicative of a network connection issue or a problem with the network configuration.

Quick Answer

To fix the "Error 101: Network is Unreachable" when updating Ubuntu with APT, you can try changing the repository mirror to the ‘Main server’ or disabling IPv6 system-wide. These solutions should help resolve the issue and allow you to update your system successfully.

Understanding the Error

The “Error 101: Network is Unreachable” is a common error that users encounter when trying to update Ubuntu using the apt-get update command. This error is usually a sign that your system is unable to establish a connection with the network, which could be due to a variety of reasons, such as an issue with your local repository mirror or a problem with your Internet Service Provider (ISP).

Solution 1: Changing the Repository Mirror

One of the simplest solutions to this problem is to change the repository to the ‘Main server’. Sometimes, local repository mirrors can experience downtime, causing the “Network is unreachable” error.

To change the repository mirror, follow these steps:

  1. Open ‘Software & Updates’ on your Ubuntu system.
  2. In the ‘Ubuntu Software’ tab, locate the ‘Download from’ dropdown menu.
  3. Change the selected option to ‘Main server’.
  4. Close the window and try running sudo apt-get update again.

This change should force your system to use the main Ubuntu repository, which is generally more reliable.

Solution 2: Disabling IPv6

Another potential cause of this error is that your machine is using IPv6 to connect to the internet, but your ISP does not support IPv6. In this case, you can disable IPv6 system-wide.

To disable IPv6, you need to edit the /etc/default/grub file and add ipv6.disable=1 to the value of GRUB_CMDLINE_LINUX_DEFAULT. Here’s how you do it:

  1. Open the terminal and type sudo nano /etc/default/grub. This command opens the grub file in the nano editor.
  2. Locate the line that reads GRUB_CMDLINE_LINUX_DEFAULT and add ipv6.disable=1 to it. It should look something like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash ipv6.disable=1"
  3. Save and exit the file by pressing Ctrl+X, then Y, and finally Enter.
  4. Run sudo update-grub. This command updates the grub and applies the changes you made.
  5. Reboot your system.

Disabling IPv6 might seem like an extreme solution, but if you’re also experiencing issues browsing the web, it might be necessary.


The “Error 101: Network is Unreachable” when updating Ubuntu with APT can be a nuisance, but it’s generally easy to fix. By changing the repository mirror or disabling IPv6, you should be able to resolve the issue and update your system successfully. If you’re still experiencing problems, it might be worth reaching out to your ISP to see if there are any known issues or contacting Ubuntu support for further assistance.

What is APT?

APT stands for Advanced Package Tool. It is a package management system used in Ubuntu and other Debian-based Linux distributions to handle the installation, removal, and updating of software packages.

How do I update the grub after making changes to the `/etc/default/grub` file?

To update the grub after making changes to the /etc/default/grub file, you can run the command sudo update-grub in the terminal. This command updates the grub configuration and applies the changes you made.

Why would I need to disable IPv6?

Disabling IPv6 might be necessary if you’re experiencing network connectivity issues or if your ISP does not support IPv6. It can help troubleshoot network-related problems and ensure compatibility with IPv4-only networks.

How can I contact Ubuntu support for further assistance?

To get further assistance from Ubuntu support, you can visit their official website at They provide various support options, including community forums, documentation, and professional support services.

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