<li>Use the Internet to search for '''TCP 3 way handshake''' to see how TCP connections are established and closed.<br><br></li>
::So far, we have learned to establish an ssh connection to another host using a password to establish your identity. But '''passwords are not the only or even the best way of authenticating your identit'''y. We can also use '''Public/Private key encryption'''.
::'''Public Key authentication''' is a method of establishing identity using a '''pair of encryption keys that are designed to work together'''. One key is known as your '''private key''' (which as the name suggests should remain private and protected) and the other is known as the '''public key''' (which as the name suggests can be freely distributed) The keys are designed to work together to encrypt data asymmetrically, that is to say that when we '''encrypt data with one of the keys it can only be decrypted with the other key''' from the pair.
::While it doesn't mean the message is <u>secure</u> as anybody could decrypt it with the public key, it does establish my <u>identity</u>, if the host can successfully decrypt the message then it must have come from the one person in possession of the private key.
::We are now going to generate a new set of public/private keys.Students run into a lot of trouble when using ssh and generating key-pairs by performing these operations as root user by Mistake!
<li>Make certain to logout of your '''centos3''' system. Use the '''hostname''' command to verify you are back in your centos2 server.</li>
'''Answer INVESTIGATION 1 observations / questions in your lab log book.'''