OpenSSH

HowTo: Disable SSH Host Key Checking

How to disable SSH host key verification and bypass "The authenticity of host ***** can't be established." and "REMOTE HOST IDENTIFICATION HAS CHANGED." messages.

Running Commands on a Remote Linux Server over SSH

In this note you will find the examples of how to execute commands on a remote Linux machine and get the result locally.

This information may be very useful if you are creating some Bash Script that should be ran from the local machine and execute some commands on a remote server.

You'll learn, how to :

  • execute a command on a remote Linux Server;
  • run multiply commands over SSH;
  • execute a local script on a remote Linux server without copying it.

SSH Login Slow -- Removing Delay

Problem : When I’m trying to log into the remote server via SSH, after I enter the UserName, it takes a lot of time before it displays the Password prompt. How to solve this problem?

Solution : Basically, a long delay during authentication process is caused by "GSS API Authentication method" or/and by "UseDNS" option. The solution is to disable the GSSAPIAuthentication method and to set the UseDNS to "no" on the SSH Server.

HowTo : Set a Warning Message (Banner) in SSH

SSH warning banners and welcome messages are necessary when organization wishes to prosecute an unauthorized user or just give out some information or announcement.

3 Steps to Perform SSH Login Without Password

It is very easy to perform SSH login to the remote server without prompting a password.

With a help of utilities from OpenSSH package, you can generate authentication keys on your local machine, copy public key to the remote server and add identities to your authentication agent.

Just three simple steps separate you from the possibility of connecting to a remote server without prompting a password.

10 Examples : Copying Files over SSH

SCP (Secure CoPy) - is a remote file copy program, that copies files between hosts on a network.

It uses SSH for data transfer, and uses the same authentication and provides the same security as SSH.

SSH with Public Key-Based Authentication

To improve the system security and to enable running automated maintenance tasks on other machines, you can use the key-based authentication instead of standard password authentication.

Key-based authentication uses two keys, one "public" key that anyone is allowed to see, and another "private" key that only the owner is allowed to see.

To securely communicate using key-based authentication, you need to create a public key for the computer you're logging in from, and securely transmit it to the computer you're logging in to.