SSH

SSH is a useful and secure tool to connect yourself via the internet or locally with your PC remotely. It is not installed on every distribution by default.

Install

sudo apt-get install ssh

Config

sudo nano /etc/ssh/sshd_config

Define port to listen, recommend to change the default port 22

If you use FTP Port as SSH Port (21) then you will run into problems with connecting via Windows PC's because of the Windows Firewall. In order to solve this problem execute the following line on Windows PC's with Admin privilege.

netsh advfirewall set global statefulftp disable

Source your `.bashrc`

Create or edit the ~/.bash_profile. And add the following line to souce with each SSH Login your .bashrc

.bash_profile

source ~/.bashrc

Test

Test you system with via the localhost.

ssh -p <portnumber> localhost

Restart SSH

sudo /etc/init.d/ssh restart

Connect

ssh -p <portnumber> -l <username> server.address.com
ssh -p <portnumber> user@server.address.com

Port Forwarding

ssh connection

ssh -N -T -L <remoteport>:localhost:<localport> <user>@<hostname>

# or with port forward and commandline
ssh -L <remoteport>:localhost:<localport> <user>@<hostname>

Options

-p <port> - Custom port definition
-l <username> - Custom username definition
-N - No Output
-T - No Terminal access
-L <remoteport>:localhost:<localport> - Port Forwarding

RSA keys

How to setup ssh with rsa keys

ssh keys

# Generating RSA Key pair
ssh-keygen -t rsa

# Copy key
ssh-copy-id -i ~/.ssh/id_rsa.pub "user@remote.machine.com -p <portnumber>"
# OR
scp id_rsa.pub user@host:~/.ssh/machine.pub

# Append key to file authorized_keys
cat ~/.ssh/*.pub | ssh admin@server.machine.com -p <portnumber> 'umask 077; cat >>.ssh/authorized_keys'

SSH