SSH public/private key

Key in your hand is Private, and DoorLock is called Public key(Lock itself).

Generating Keypair:

ssh-keygen -t rsa -b 4096 -f ~/.ssh/github1 -C "my@mail.com" 

-t: rsa algo name

-b: 2048 enctyption bits

-C: Comments

Upload the key to your server

Once an SSH key has been created, the ssh-copy-id command can be used to install it as an authorized key on the server.

First, make user1 owner to the ~/.ssh folder.

 mg@node2:~$ sudo mkdir -p /home/user1/.ssh
 mg@node2:~$ sudo chown fresh:users -R /home/user1/.ssh/
 mg@node2:~$ sudo chmod -R 700 /home/user1/.ssh/
 mg@node2:~$ ls -al /home/user1

Edit the sshd config:

sudo vi /etc/ssh/sshd_config
      -> PasswordAuthentication no
sudo service sshd restart

From client (git-bash client) system:

$ ssh-copy-id -i /c/Users/Rita/On...ve/P...ming/SSH/xkeyx.pub user1@113.15.51.51

(enter pass if required) After a successful install, it will show the bellow message.

Disable Password authentication, Inside the /etc/ssh/sshd_config file:

sudo vi /etc/ssh/sshd_config
      -> PasswordAuthentication no
sudo service sshd restart

[

(ssh-copy for another user https://measure9.varkel.net/2017/09/ssh-copy-id-key-to-other-user-than-yourself/)

cat ~/.ssh/node2.pub | ssh -i ~/.ssh/node2 

mg@192.168.10.115 sudo tee -a /home/life110volts/.ssh/authorized_keys

(or from Windows pc)

scp C:\Users\MyUserName\.ssh/id_rsa.pub example_user@203.0.113.100:~/.ssh/authorized_keys

]

SSH activities

Adding a private key to SSH Agent:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/github1
passcode: d******3

To list the ssh-keys

$ ssh-add –l
$ ls -l ~/.ssh

To remove a key from the ssh-agent,

$ ssh-add -d /home/user/.ssh/id_rsa
(To remove all)
$ ssh-add –D

Kill the ssh-agent

Keeping the private keys secure is important. It is suggested that the ssh-agent is terminated or locked when it is not needed anymore. 

$ eval $(ssh-agent -s -k)

Add the private key to GitHub.

MacOS: Pbcopy < ~/.ssh/id_rsa.pub
Windows: clip < ~/.ssh/id_rsa.pub
ssh -T git@github.com
ssh -T hg@bitbucket.org

Test login

ssh -T -i ~/.ssh/github1 hg@bitbucket.org  

Login Directly without a key agent.

ssh -T -i ~/.ssh/github1 hg@bitbucket.org  
ssh -T -i ~/.ssh/github1 git@github.com

Login with ssh and deploy to a Godaddy instance:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/gokkdy
ssh -i ~/.ssh/godkkdy bangkkking@107.1k.k0.1k

After connected to GoDaddy.

cd /home/bsdfsdfng/#mydomains/dudfhool.com
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/cmdfinc.com
ssh -T -i ~/.ssh/cmarinc.com hg@bitbucket.org
git pull upstream master