When trying to connect to a server via SSH (Secure Shell), you may encounter a frustrating “Permission Denied” error. This error can prevent you from accessing your server and disrupt your workflow. In this blog post, we’ll explore the common causes of the “Permission Denied” error in SSH and provide step-by-step solutions to help you regain access to your server.
Table of Contents
Understanding the “Permission Denied” Error
The “Permission Denied” error typically indicates that the SSH client is unable to authenticate the user for one of the following reasons:
- Incorrect username or password.
- Problems with SSH keys.
- Misconfigured permissions on your SSH configuration files or directories.
- Issues with the SSH server configuration.
Common Causes of “Permission Denied” Errors
1. Incorrect Username
One of the most common causes of the “Permission Denied” error is entering the wrong username when attempting to connect.
Solution:
- Double-check the username you are using. Make sure it matches the account on the server exactly, including case sensitivity.
2. Wrong Password
If you are using password authentication, entering an incorrect password will result in a “Permission Denied” error.
Solution:
- Verify that you are typing the correct password. Remember that SSH is case-sensitive.
- If you’ve forgotten your password, you may need to reset it through your server’s control panel or by contacting your system administrator.
3. SSH Key Issues
If you’re using key-based authentication, several issues can lead to the “Permission Denied” error:
- The private key is not being used or is incorrect.
- The public key is not present in the
~/.ssh/authorized_keysfile on the server. - Permissions on the private key are too open.
Solution:
Ensure you are using the correct private key with the -i option:
ssh -i /path/to/private_key username@hostname
Check that your public key is correctly added to the server’s ~/.ssh/authorized_keys file. You can view this file on the server using:
cat ~/.ssh/authorized_keys
Verify that the private key file has the correct permissions set to 600:
chmod 600 /path/to/private_key
4. File Permissions Issues
Improper permissions on your .ssh directory or the authorized_keys file can prevent SSH from authenticating correctly.
Solution:
Ensure that your ~/.ssh directory has permissions set to 700 :
Ensure that your ~/.ssh/authorized_keys file has permissions set to 600:
5. SSH Server Configuration
Sometimes, the SSH server’s configuration can block access. For instance, the server may not allow the user to log in due to settings in the sshd_config file.
Solution:
- Check the server’s SSH configuration file located at
/etc/ssh/sshd_configfor settings likeAllowUsers, which restricts SSH access to specific users. - Make sure the user you are trying to connect with is not restricted by this setting.
- After making any changes, restart the SSH service with:
6. Account Lockout
If you’ve attempted to log in multiple times with incorrect credentials, your account may be temporarily locked.
Solution:
- Wait for the lockout period to expire, or check with your system administrator to unlock the account.
7. Firewall or Security Group Issues
In cloud environments, security groups or firewall settings might block SSH access, leading to a “Permission Denied” error.
Solution:
- Verify that port 22 (or your configured SSH port) is open in your firewall settings. If you’re using a cloud service, check the security group settings to ensure SSH access is allowed.
Conclusion
Encountering a “Permission Denied” error when trying to connect via SSH can be frustrating, but most issues can be resolved with a systematic approach. By checking your username, password, SSH keys, file permissions, server configuration, and network settings, you can troubleshoot and fix the problem effectively.
If you continue to experience issues, consider seeking assistance from your system administrator or your hosting provider. With the right steps, you’ll be back to accessing your server securely in no time!
