- Generate Public and Private Keys
- Copy Public Key to the target machine
- Set appropriate permissions
- Create Configuration File for auto login
- Tunnel connections
SSH keys allow you to login into your SSH server without having to remember passwords and with much stronger security. It’s like having a super long password that you never have to remember… Just keep your private keys in a safe place.
Generate Public and Private Keys
Generate public keys. The command will produce two keys, one public (
~/.ssh/example.com-id.pub) and one private (
1 ssh-keygen -f ~/.ssh/example.com-id
Copy Public Key to the target machine
Your remote server needs to know your public key, so you need to send it there.
1 2 #copy the public key to the target machine ssh-copy-id -i ~/.ssh/example.com-id.pub firstname.lastname@example.org
Set appropriate permissions
Your private key should only be visible to you and not other users, otherwise
ssh will complain and not allow you to use the keys.
1 2 chmod 0700 ~/.ssh/ chmod 0600 ~/.ssh/example.com-id
Create Configuration File for auto login
This config file will tell
ssh where are the configurations for an alias for your now key-authenticated server.
1 vim ~/.ssh/config
Example contents of the new file
1 2 3 4 5 6 7 8 9 10 11 #alias of the machine into which you are logging in Host example.com #hostname or ip of the machine HostName example.com #the username with which you are logging in User exampleuser #the private key, without "-pub" IdentityFile ~/.ssh/example.com-id
Login using machine identifier
Now you can login using
ssh and the alias you choose in the config file above.
1 ssh example.com
Save your keys and configuration file in a “safe place” for later
You can login from other computers using the same public key without having to configure the server again. All you need is to copy:
- The public (
~/.ssh/example.com-id.pub) and private keys (
~/.ssh directory in the new machine.
Disable remote login using passwords
1 vim /etc/ssh/sshd_config
Search for the line below and uncomment
1 2 # Change to no to disable tunnelled clear text passwords #PasswordAuthentication no #change to PasswordAuthentication no without the hash
Restart the sshd service
1 sudo service ssh restart
Remember, if others also get these keys and configuration file they can log into your server!
Tunnel connections are really cool if you have a server running somewhere and you need to access that server as if it was running on your own computer!
Configuring the remote machine
We need to configure the
sshd service to enable TCP connections forwarding. Start by editing
1 sudo vim /etc/ssh/sshd_config
Enable these row:
1 2 AllowTcpForwarding yes TCPKeepAlive yes
1 sudo service sshd restart
Opening the tunnel
With username + password:
1 ssh -L 5901:127.0.0.1:5901 -C -N -l username server_address
With with a public key configuration:
1 ssh -L 5901:127.0.0.1:5901 -C -N dendro-builder.fe.up.pt -v