How to Fix Permission Denied (publickey) Error in SSH Connections

✨ Quick Answer

The Permission denied (publickey) error when trying to connect to a remote server via SSH occurs because the SSH daemon (sshd) on the remote server rejects the private key presented by your client. This is usually due to file permissions being too permissive, which invalidates the security of the connection and forces the server to discard the attempt for protection.

Quick Diagnostics

Cause

Overly permissive file permissions on private key (~/.ssh/id_rsa)

Solution

Set strict permissions on private key: chmod 600 ~/.ssh/id_rsa

Cause

Public key missing from remote server's authorized_keys

Solution

Copy public key to server: ssh-copy-id user@server

The Permission denied (publickey) error when trying to connect to a remote server via SSH occurs because the SSH daemon (sshd) on the remote server rejects the private key presented by your client. This is usually due to file permissions being too permissive, which invalidates the security of the connection and forces the server to discard the attempt for protection.

Step-by-Step Solution

1. 1

   Step 1: Corregir los permisos de tu clave privada en el cliente

   The private key must never be readable by other users of the local machine. Adjust the permissions of the .pem or id_rsa file:

   BASH Copy

   # Cambiar permisos para que solo el propietario pueda leer el archivo
   chmod 600 ~/.ssh/id_rsa
   

2. 2

   Step 2: Ajustar los permisos del directorio .ssh y autorizaciones en el servidor

   Access the server console (through TTY or the hosting provider's console) and run the following fixes on your home directory:

   BASH Copy

   # Asegurar el directorio de configuración de SSH
   chmod 700 ~/.ssh
   
   # Asegurar el archivo que almacena las claves autorizadas
   chmod 600 ~/.ssh/authorized_keys
   
   # Restablecer la propiedad de los archivos a tu usuario actual
   chown -R $USER:$USER ~/.ssh
   

3. 3

   Step 3: Comprobar la directiva de autenticación en el servidor

   If the error persists, edit the SSH service configuration file on the server /etc/ssh/sshd_config and verify that public key authentication is enabled:

   PLAINTEXT Copy

   PubkeyAuthentication yes
   AuthorizedKeysFile .ssh/authorized_keys
   

   Restart the service to apply the changes:

   BASH Copy

   sudo systemctl restart sshd