How to fix "Remote Host Identification Has Changed" Issue with GitHub and Git

Introduction:

Git and GitHub are being used more and more frequently by developers to collaborate on projects, thus seeing different error messages is unavoidable. The error "Remote Host Identification Has Changed" is one error that can be annoying.

In this blog post, we will examine the reasons for this problem and offer detailed steps on how to successfully resolve it when using Git CLI & GitHub.

Causes of the Error:

The "Remote Host Identification Has Changed" error occurs when the fingerprint of the remote host (GitHub) you are connecting to has changed. There are a few common causes for this:

• Server Changes: GitHub might update its server infrastructure, leading to changes in host fingerprints.
• Security Updates: GitHub periodically enhances its security measures, which can result in altered fingerprints.
• Man-in-the-Middle Attacks: In rare cases, this error can indicate an unauthorized entity intercepting your connection, posing a security risk.

How to Fix the Error:

To fix the "Remote Host Identification Has Changed" error, follow these steps:

• Clear Old SSH Fingerprints: Remove the outdated SSH fingerprints stored on your local machine. Use the following command to delete the relevant line from your known_hosts file:
  ssh-keygen -R github.com

• Establish a new connection to GitHub to update the SSH known_hosts file with the new fingerprint. You can do this simply by attempting make a connection the a remote repository using SSH e.g push, pull, clone. The updated fingerprint will be automatically added.
  The authenticity of host 'github.com (20.201.28.151)' can't be established.
ED25519 key fingerprint is SHA256:br9IjFspm1vxR3iA35FWE+4VTyz1hYVLIE2t1/CeyWQ.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])?

• Verify the New Fingerprint: After updating the SSH known_hosts file, verify the authenticity of the new fingerprint. GitHub provides instructions on how to verify fingerprints for different operating systems.

Make sure it matches one of GitHub's public key fingerprints:

• SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s (RSA)
• SHA256:br9IjFspm1vxR3iA35FWE+4VTyz1hYVLIE2t1/CeyWQ (DSA - deprecated)
• SHA256:p2QAMXNIC1TJYWeIOttrVc98/R1BUFWu3/LiyKgUfQM (ECDSA)
• SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU (Ed25519)

Avoiding the Error:

To prevent encountering the "Remote Host Identification Has Changed" error in the future, consider these practices:

• Regularly Update Your SSH Known Hosts: Periodically updating the SSH known_hosts file ensures that you have the most up-to-date fingerprints stored locally.
• Enable Two-Factor Authentication (2FA): Enabling 2FA adds an extra layer of security to your GitHub account, reducing the risk of unauthorized access.
• Stay Informed: Keep track of GitHub announcements and updates to stay informed about any changes that may affect host fingerprints.

Conclusion:

The "Remote Host Identification Has Changed" error in GitHub can be resolved by understanding its causes and following the provided steps to fix it. Additionally, adopting preventive measures like regularly updating your SSH known_hosts file and staying informed about GitHub changes will help you avoid this error in the future. By mastering these troubleshooting techniques, you can ensure secure and uninterrupted collaboration on your Git projects with GitHub.