How to Disable IPv6 on Ubuntu 24.04

by

Ubuntu 24.04, like its predecessors, supports IPv6 by default. However, there are times when you might need to disable IPv6, whether for compatibility reasons, testing purposes, or specific network requirements. This comprehensive guide will walk you through the steps to check if IPv6 is enabled on your system, how to disable it, and how to verify that it has been disabled.

In this tutorial you will learn:

  • How to check if IPv6 is currently enabled on Ubuntu 24.04
  • Steps to disable IPv6 on Ubuntu 24.04
  • How to confirm if IPv6 has been disabled
How to Disable IPv6 on Ubuntu 24.04
How to Disable IPv6 on Ubuntu 24.04
  1. Checking if IPv6 is Enabled: First, you need to check if IPv6 is active on your system. Open the terminal and enter ip addr. Look for inet6 in the output, which indicates that IPv6 is enabled. 
    $ ip addr

    Checking if IPv6 is Enabled
    Checking if IPv6 is Enabled
  2. Editing the sysctl Configuration File: To disable IPv6, edit the sysctl configuration. Use the command sudo nano /etc/sysctl.conf to open the file in the nano editor. You can substitute nano with any other text editor. 
    $ sudo nano /etc/sysctl.conf
  3. Adding IPv6 Disable Parameters: At the end of the sysctl configuration file, add the following lines: 
    net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

    These lines disable IPv6 on all interfaces, including the loopback interface.

  4. Applying the Configuration Changes: Save the changes and close the file. Apply the new settings by executing sudo sysctl -p in the terminal. 
    sudo sysctl -p


    Applying the Configuration Changes
    Applying the Configuration Changes
  5. Verifying that IPv6 is Disabled: Finally, verify that IPv6 has been disabled by running cat /proc/sys/net/ipv6/conf/all/disable_ipv6. If it returns 1, IPv6 is disabled. 
    $ cat /proc/sys/net/ipv6/conf/all/disable_ipv6
or
$ ip addr

    Verifying that IPv6 is Disabled
    Verifying that IPv6 is Disabled

Conclusion

Following these steps will effectively disable IPv6 on your Ubuntu 24.04 system. While disabling IPv6 is necessary in some scenarios, keep in mind that it’s crucial for modern internet communication and its use is growing. Therefore, consider the implications of this action in your network environment.

Frequently Asked Questions (FAQs) – Disabling IPv6 on Ubuntu 24.04

  1. Why would I need to disable IPv6 on Ubuntu 24.04?

    Disabling IPv6 might be necessary for compatibility with certain networks or applications that don’t support IPv6, for testing purposes, or to address specific network performance issues.

  2. Is it safe to disable IPv6 on my system?

    While disabling IPv6 is generally safe, it’s important to understand that IPv6 is the future of internet protocols. Disabling it might lead to limitations in network functionality, especially as the world transitions more towards IPv6.

  3. Will disabling IPv6 affect my internet speed?

    Disabling IPv6 should not significantly affect your internet speed. However, some modern websites and services are optimized for IPv6, so there might be a negligible impact on how these sites perform.

  4. Can I re-enable IPv6 after disabling it?

    Yes, you can easily re-enable IPv6 by reversing the steps taken to disable it, primarily by editing the sysctl configuration file and setting the IPv6 parameters back to 0.

  5. How do I check if IPv6 is disabled on my system?

    To verify if IPv6 is disabled, run the command cat /proc/sys/net/ipv6/conf/all/disable_ipv6 in your terminal. An output of ‘1’ means IPv6 is disabled.

  6. Do I need to restart my computer after disabling IPv6?

    No, a restart is not necessary. Applying the sysctl configuration with sudo sysctl -p is sufficient for the changes to take effect.

  7. Will disabling IPv6 on Ubuntu 24.04 affect other devices on my network?

    No, disabling IPv6 on your Ubuntu system will only affect that specific machine. Other devices on your network will continue to use their current IPv6 settings.

  8. What should I do if I encounter problems after disabling IPv6?

    If you encounter issues after disabling IPv6, consider re-enabling it to see if the issues persist. If problems continue, it might be worth consulting with a network specialist or seeking support from the Ubuntu community.


Related Linux Tutorials: