ssh

Public / Private Key Authentication

** public key stored on server
** private key stored locally

Server:
- cd
- mkdir .ssh
- exit

Client:
- ssh-keygen -b 4096 rsa
- cd .ssh/
        id_rsa  id_rsa.pub  known_hosts

- cd
- scp .ssh/id_rsa.pub emre@ip:/home/emre/.ssh

Server:
- cd .ssh/
- ls
        id_rsa.pub
- mv id_rsa.pub authorized_keys
- chmod 400 authorized_keys
- (check .ssh file permission is 700)
- sudo chattr +1 authorized_keys
- cd /etc/ssh
- sudo vi sshd_config
and open file uncomment AuthorizedKyesFile %h/.ssh/authorized_keys
PasswordAuthentication yes to no

For Ubuntu 18.04
AuthorizedKyesFile .ssh/authorized_keys .ssh/authorized_keys2
AuthorizedKyesFile %h/.ssh/authorized_keys .ssh/authorized_keys2
PasswordAuthentication yes to no


- sudo systemctl restart ssh


# Permission denied (publickey),
- ssh -i .ssh/id_rsa emre@ip

Client 
- cd ~/.ssh
- vi config

Host nginx
HostName 35.236.64.179
User emre
IdentityFile ~/.ssh/id_rsa
ServerAliveInterval 60
ServerAliveCountMax 120

- ssh nginx


# Firewall Configs (server)
- sudo ufw status verbose
- sudo vi /etc/default/ufw
IPV6=yes to no
- sudo ufw default deny incoming
- sudo ufw default allow outgoing
- sudo ufw allow http
- sudo ufw allow https
- sudo ufw enable
- sudo ufw status
- sudo reboot