SSH

SSH

SSH allows you to connect to a shell on a remote computer.

Example: [user@localhost ~]$ ssh username@yourserver

Use -p to set the port.

Example: [user@localhost ~]$ ssh -p 123 username@yourserver - connects using port 123.

SCP

You can also use scp to securely transfer files.

Example:

scp examplefile yourusername@yourserver:/home/yourusername/

This example sends examplefile from the directory you're currently in to /home/yourusername/ on yourserver

Note that scp uses -P to specify the port.

To download a file from a remote server to your local computer:

scp sshusername@10.10.10.123:/remote/file.txt /home/user/Downloads/

SSH Keys

ssh keys are used to connect to an ssh server without a password.

Step 1: Create a key-pair on the client machine

ssh-keygen -t rsa

After you enter the above command, ssh-keygen will ask you where you want to store the key. You can just press ENTER to accept the default location.

Next, it will ask you to enter a passphrase. You can either enter a passphrase, or press ENTER to not use a passphrase. (Note that you don't need a pass-phrase, but if you don't use one, anyone that somehow gets a copy of the key can get into your server.)

SSH keygen will spit out a bunch of stuff, and you're done with step 1.

Step 2: Copy the public key to the server

ssh-copy-id user@server_IP

This will copy the public key over to the server. Now try to connect via SSH, and it should connect without a password (unless you entered a pass-phrase. In that case, you need to enter the pass-phrase to connect.)

References

1. ssh man page