SSH (secure shell) for making encrypted connection between 2 computers by using a secure channel between these computers for (remote access, copying files, etc..).
SSH is based on client server model: server (SSHD) and clients (scp,sftp,ssh)
Why SSH: SSH with it’s sub-system (scp , sftp ) is instead of (telnet, ftp, rcp ) and protocols that run these program are insecure. Telnet for example uses non encrypted channel to connect with another computer, so man in the middle attack can intercept telnet messages and can get sensitive information such as username and password.
SSH key generator generate keys by command ssh-keygen -t rsa and then follow the default configuration.
Generating public/private rsa key pair. Enter file in which to save the key (/home/example/.ssh/id\_rsa): Created directory '/home/example/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/example/.ssh/id\_rsa. Your public key has been saved in /home/example/.ssh/id\_rsa.pub. The key fingerprint is: 5e:3f:6f:57:42:d0:b2:f5:aa:98:53:0f:20:5d:b0:2a example@example it will generates 2 files in ~/.
SSH Port Forwarding/SSH tunneling Allow to establish SSH session (secured connection) and then making TCP connection (unsecured connection) inside the tunnel or through it, it’s used for securing unsecured connection.
Local Port Forwarding To understand port forwarding let’s see examples, when i want to access my mail client via pop (post office protocol) port 110, so to secure this connection, i should first establish SSH session, and then make a normal TCP connection through this channel
