How to set up Passwordless SSH Login in Linux

To set up a passwordless SSH login in Linux all you need to do is to generate a public authentication key and append it to the remote hosts ~/.
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Setup SSH Passwordless Login

Check for existing SSH key pair. ...
Generate a new SSH key pair. ...
Copy the public key. ...
Login to your server using SSH keys.

How set Passwordless Sftp in Linux?
How does SSH Passwordless work?
How do I login using SSH key?
How do I setup a SSH connection between two servers?
How can I use SFTP without password?
How do I pass a username and password in SFTP?
How do I generate an SSH key?
How do I set up automatic ssh?
How do I protect my SSH private key?
How do I find my SSH key?
What format is my private key?
Where do I put the public key on my server?

How set Passwordless Sftp in Linux?

Passwordless SSH/SFTP Access in Linux

On the bash shell of the machine and account you want to ssh/sftp FROM (e.g. your laptop), generate an ssh key pair if you don't already have one: ...
Copy your public key to the server you want to login TO using the ssh-copy-id program: ...
Login to the machine to make sure it is working properly:

How does SSH Passwordless work?

When password-less mode is configured, a given user on a given client server can connect through SSH to a given server without explicitly providing the password, because server has a way (through private/public key) to authenticate the client (validate that "you are who you say you are").

How do I login using SSH key?

Using ssh-copy-id

To use ssh-copy-id , pass your username and the IP address of the server you would like to access: ssh-copy-id [email protected].
You'll see output like the following, and a prompt to enter your user's password: ...
Verify that you can log in to the server with your key.

How do I setup a SSH connection between two servers?

Step by step guide for establishing passwordless ssh between two Unix or Linux servers. Authenticate securely using public and private keys.
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Lets see how to setup password less ssh between two servers:

Create your SSH key pair on the source machine. ...
Now, we need to copy id_rsa. ...
You are done!

How can I use SFTP without password?

To get SSH or SFTP access to a server without using a password you need to have a SSH key pair for each computer you want to be able to access the server from.
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Generate an SSH key pair on *nix

Step 1: Check for existing SSH keys. ...
Step 2: Generate a new SSH key pair. ...
Step 3: Copy your SSH key.

How do I pass a username and password in SFTP?

export SSHPASS=your-password-here sshpass -e sftp -oBatchMode=no -b - sftp-user@remote-host << ! cd incoming put your-log-file.
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10 Answers

Use keychain.
Use sshpass (less secured but probably that meets your requirement)
Use expect (least secured and more coding needed)

How do I generate an SSH key?

Windows (PuTTY SSH Client)

On your Windows workstation, go to Start > All Programs > PuTTY > PuTTYgen. The PuTTY Key Generator displays.
Click the Generate button and follow the instructions. ...
Click Save Private Key to save the private key to a file. ...
Close the PuTTY Key Generator.

How do I set up automatic ssh?

How to Set Up Passwordless SSH Login

Before You Start: Check for Existing SSH Keys.
Step 1: Generate SSH Key Pair.
Step 2: Upload Public Key to Remote Server. Option 1: Upload Public Key Using the ssh-copy-id Command. ...
Step 3: Log in to Server Without Password.
Optional: Troubleshooting Remote Server File Permissions.

How do I protect my SSH private key?

The unencrypted private key format. Everyone recommends that you protect your private key with a passphrase (otherwise anybody who steals the file from you can log into everything you have access to). If you leave the passphrase blank, the key is not encrypted.

How do I find my SSH key?

Checking for existing SSH keys

Open .
Enter ls -al ~/.ssh to see if existing SSH keys are present: $ ls -al ~/.ssh # Lists the files in your .ssh directory, if they exist.
Check the directory listing to see if you already have a public SSH key. By default, the filenames of the public keys are one of the following: id_rsa.pub. id_ecdsa.pub.

What format is my private key?

PKCS #12. This is also known as PFX. This format can contain private keys (RSA or DSA), public keys (RSA or DSA) and X. 509 certificates.

Where do I put the public key on my server?

Your public key should be copied at the appropriate folder on the remote server automatically. I have used ~/. ssh/id_rsa. pub because that is the default location for the public ssh key.