SSH Passwordless Login Using SSH Keygen in 5 Easy Steps

SSH (Secure SHELL) is an open source and most trusted network protocol that is used to login into remote servers for execution of commands and programs. It is also used to transfer files from one computer to another computer over the network using secure copy (SCP) Protocol.

In this article we will show you how to setup password-less login on RHEL/CentOS 7.x/6.x/5.x and Fedora usingssh keys to connect to remote Linux servers without entering password. Using Password-less login with SSH keys will increase the trust between two Linux servers for easy file synchronization or transfer.

SSH Passwordless Login

My Setup Environment
SSH Client : ( Fedora 21 )
SSH Remote Host : ( CentOS 7 )

If you are dealing with number of Linux remote servers, then SSH Password-less login is one of the best way to automate tasks such as automatic backups with scripts, synchronization files using scp and remote command execution.

In this example we will setup SSH password-less automatic login from server as user tecmint to192.168.0.11 with user sheena.

Step 1: Create Authentication SSH-Kegen Keys on – (

First login into server with user tecmint and generate a pair of public keys using following command.

[ ~]$ ssh-keygen -t rsa

Generating public/private rsa key pair.
Enter file in which to save the key (/home/tecmint/.ssh/id_rsa): [Press enter key]
Created directory '/home/tecmint/.ssh'.
Enter passphrase (empty for no passphrase): [Press enter key]
Enter same passphrase again: [Press enter key]
Your identification has been saved in /home/tecmint/.ssh/id_rsa.
Your public key has been saved in /home/tecmint/.ssh/
The key fingerprint is:
The key's randomart image is:
+--[ RSA 2048]----+
|        ..oooE.++|
|         o. o.o  |
|          ..   . |
|         o  . . o|
|        S .  . + |
|       . .    . o|
|      . o o    ..|
|       + +       |
|        +.       |

Create SSH RSA Key

Step 2: Create .ssh Directory on –

Use SSH from server to connect server using sheena as user and create .sshdirectory under it, using following command.

[tecmint@tecmint ~]$ ssh sheena@ mkdir -p .ssh

The authenticity of host ' (' can't be established.
RSA key fingerprint is 45:0e:28:11:d6:81:62:16:04:3f:db:38:02:la:22:4e.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '' (ECDSA) to the list of known hosts.
sheena@'s password: [Enter Your Password Here]

Create SSH Directory Under User Home

Step 3: Upload Generated Public Keys to –

Use SSH from server and upload new generated public key ( on server sheena‘s .ssh directory as a file name authorized_keys.

[tecmint@tecmint ~]$ cat .ssh/ | ssh sheena@ 'cat >> .ssh/authorized_keys'

sheena@'s password: [Enter Your Password Here]

Upload RSA Key

Step 4: Set Permissions on –

Due to different SSH versions on servers, we need to set permissions on .ssh directory and authorized_keys file.

[tecmint@tecmint ~]$ ssh sheena@ "chmod 700 .ssh; chmod 640 .ssh/authorized_keys"

sheena@'s password: [Enter Your Password Here]

Set Permission on SSH Key

Step 5: Login from to Server without Password

From now onwards you can log into as sheena user from server as tecmint user without password.

[tecmint@tecmint ~]$ ssh sheena@

SSH Remote Passwordless Login


Posted on June 12, 2015, in Linux (Ubuntu/CentOS). Bookmark the permalink. Leave a comment.

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