How to resolve SSH warning during connecting to AWS instance

In this tutorial I will explain you about how to connect to an AWS instance using a private key form your Linux machine. During SSH you might got the below type of SSH warning.

To resolve this type of issue you need to set 400 permision on the private key. Type the below command […]
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Authenticate your SSH with Google Authenticator’s Two-Factor Authentication

Google is providing an opensource application named “Google Authenticator” which is based two-step authentication token. We can use this application to secure our server SSH. Authenticator provides a six digit number which users must provide in addition to their username and password to log into the Server. We need to install Google Authenticator PAM module […]
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How to change the SSH Banner on Ubuntu

We are getting a welcome message when we are connecting to our server through ssh client. Generally the message is of 3 lines as below.        

We can eaisly modify the message as our requirement. To modify the message we have to edit two files named “/etc/motd” and “/etc/ssh/sshd_config”

Add […]
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How to block users having OpenSSH key login

For security reasons many server administrators are preferring OpenSSH key login to their servers. Generally for OpenSSH key login we are using authorized_keys file. By appending keys to this file we will able to ssh a server. The default location of the authorized_keys file is ~/.ssh/authorized_keys. To find and print all authorized_keys file from your […]
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