Debug1: Key_load_public: No Such File Or Directory

Debug1: key_load_public: No Such File or Directory: Troubleshooting SSH Key Issues

This error, "debug1: key_load_public: no such file or directory," is a common frustration for users attempting to connect via SSH (Secure Shell). It signifies that your SSH client can't find the public key file it's trying to use for authentication. This comprehensive guide will walk you through the troubleshooting steps to resolve this issue and securely establish your SSH connection. This article covers various operating systems and common scenarios.

What Causes This Error?

The root cause is always the same: the SSH client cannot locate the specified public key file at the designated path. This can stem from several issues:

• Incorrect File Path: The most frequent problem is a simple typo in the file path specified in your SSH configuration.
• Missing Key File: The key file itself might be missing, perhaps due to deletion or incorrect placement.
• Incorrect Permissions: The key file might exist, but the permissions might prevent the SSH client from accessing it.
• Agent Issues: Your SSH agent, responsible for managing your keys, might not be running or properly configured.
• Wrong Key Type: You might be trying to use the wrong key type (e.g., using a private key file where a public key is expected).

Troubleshooting Steps: A Systematic Approach

Let's tackle the problem methodically:

1. Verify the File Path:

• Locate your SSH key files: These are typically found in ~/.ssh/ on Linux and macOS, and C:\Users\<username>\.ssh\ on Windows.
• Check for typos: Double-check the path specified in your SSH configuration files (e.g., ~/.ssh/id_rsa.pub). Case sensitivity matters!
• Identify the correct key file: The error message usually indicates which key file it's looking for. Confirm the existence of this file. The relevant file is usually a .pub file (public key).

2. Check File Existence and Permissions:

• Use the command line: Navigate to your .ssh directory using cd ~/.ssh (Linux/macOS) and verify the existence of the public key file using ls -l. On Windows, use the File Explorer.
• Permissions: Ensure the file has the correct permissions. The owner should have read access (at minimum). Use chmod 600 <key_file> (Linux/macOS) to set the permissions accordingly. On Windows, adjust the permissions through the file properties.

3. Regenerate Your SSH Keys (If Necessary):

If you're unsure about the integrity of your keys, consider regenerating them. This is a secure practice, especially if you suspect compromise. Use the following commands (replace id_rsa with your preferred key name):

• Linux/macOS:
  • ssh-keygen -t rsa -b 4096 (RSA key, recommended)
  • ssh-keygen -t ed25519 -b 4096 (Ed25519 key, faster and considered more secure)
• Windows: Use an SSH client like PuTTYgen to generate keys.

4. SSH Agent Configuration:

• Start the SSH agent: If using an SSH agent (like ssh-agent), ensure it's running. You may need to start it manually and add your private key.
• Troubleshooting agent issues: Search online for troubleshooting guidance specific to your operating system and SSH client related to agent configuration.

5. Configuration Files:

• Check your ~/.ssh/config file: If you use a config file to manage your SSH connections, ensure the IdentityFile directive points to the correct path of your private key (not the public key).
• Correct Syntax: Ensure the correct syntax in your configuration file. A single misplaced character can lead to errors.

6. Consider Other SSH Clients:

If you are using a specific SSH client (like PuTTY on Windows) and consistently face this issue, try a different client to rule out client-specific problems.

Prevention is Key:

• Back up your keys: Regularly back up your SSH keys to a safe location.
• Securely store keys: Use strong passwords and consider using a password manager.

By carefully following these steps, you can systematically identify and resolve the "debug1: key_load_public: no such file or directory" error and re-establish your SSH connection. Remember to replace placeholders like <key_file> with your actual file names. If the problem persists, provide more context (operating system, SSH client, specific commands used) for more tailored assistance.