Update index.md (#32849)

guide/english/bash/bash-ssh/index.md

@@ -2,7 +2,7 @@
 title: Bash ssh (Secure SHell)
 ---
 
-## Bash command: ssh
+# Bash command: ssh
 
 SSH (**S**ecure **SH**ell) is a secure method of remotely connecting to a Linux machine. 
 
@@ -31,14 +31,57 @@ on the computer with ip address 192.168.0.101, type the following command at a s
 
 After authenticating to the remote server, the contents of the remote directory will be displayed, and you will return to your local shell prompt.
 
-
 * Hostname can be either an IP address or a FQDN. 
 * 'username@' can be excluded if the user currently logged into the shell has the same username as the desired user on the remote system.
 * if the server is configured to listen to any port other than `22`, then you have to use `-p` option to specify the port. For example: `ssh -p 2024 123.456.789.012`.
 
 SSH can rely on password-based authentication or key-based authentication. Password-based authentication is becoming less common as cloud solutions such as Amazon Web Services, Microsoft Azure, and Google Cloud Platform promote the usage of keys. If a system is configured for password-based authentication, once the connection is opened the system will prompt the user for the password. If the system is configured to use keys, the key can be added to the ssh-agent (more below) or specified with the -i switch like so: `ssh -i my_private_key.pem username@hostname`.
 
-There are several advanced usage patterns such as key forwarding with the ssh-agent, which are described in the links below.
+## Logging in without a password
+
+It is also possible to set up your Linux servers to connect without entering a password.
+
+This can be important when servers need to connect to each other without user input.
+
+Examples of this include:
+- transferring files back and forth (using SCP)
+- using automatic scripts for backups
+
+### Step 1 - Generate an SSH authentication-key file
+
+```sh
+[user@server1 ~]$ ssh-keygen
+```
+When you are prompted for a passphrase, leave it blank
+
+By default the key files should be stored in `/home/user/.ssh/`
+
+### Step 2 - Copy the public part of the key to other servers
+
+```sh
+[user@server1 ~]$ ssh-copy-id -i ~/.ssh/id_rsa.pub user@server2
+```
+
+If the server is not installed with openssh-clients you can copy the authentication key with  the command:
+```sh
+[user@server1 ~]$ cat ~/.ssh/id_rsa.pub | ssh user@server2 "cat >> ~/.ssh/authorized_keys"
+```
+
+### Step 3 - Verification
+Attempt to connect to the other servers va SSH
+```sh
+[user@server1 ~]$ ssh user@server2
+```
+
+If access is denied, it is likely a permission error on the .ssh directory.
+
+Check/change the permissions on both the local and remote user's files:
+```sh
+chmod 600 ~/.ssh/authorized_keys
+chmod 700 ~/.ssh/
+```
+
+Try to connect again after the permission change.
 
 ### More Information:
 * [Wikipedia](https://en.wikipedia.org/wiki/Secure_Shell)