Hey everyone and welcome back. So what we're going to focus in on in this skill right here
is all about SSH that is Secure Shell. Now we do have some familiarity with Secure Shell
of course but in this skill right here we're going to look at the details of the connections
in a little bit more detail. So with that said how about we dive on and then so the
very first thing that you should know about SSH is that this is something we use for remote
connection. So this is remote access we're dealing with here. Now technically you can
just SSH back into your local system but realistically we're talking about making a connection to
a different computer to a different network that type of thing and the big thing here is
that SSH as the name does imply is indeed secure because before we actually had SSH we had
this RETCHID technology I would say at least now called Telnet. Now Telnet perhaps I'm
being a little bit unfair. Telnet did provide a good service it allowed us to have remote
connectivity but the reality is Telnet was unencrypted. Now in today's day and age we
know that we can't deal with these unencrypted connections because quite simply they are
just nowhere near secure enough you are just inviting trouble into your network and depending
on the actual industry in which you are in potentially opening yourself up to accusations
of malpractice and potentially litigation so really you want to have your security in
order. So one of the best things that you can do for security as you may know is to
invoke encryption and that is what SSH was all about. So really what we have here is
we have a server this can be called server one again because as we know by now I'm just
so creative and we could have over here let's just call this you guessed it server two.
If server one wants to log in to server two all we do is we set up this type of tunnel
and this tunnel is going to be an SSH tunnel. Now once we open this up you can visualize
this as like an encrypted pipe so that means that you can actually send information through
this channel and all the data here is going to be protected by the outer layers of the
SSH tunnel. So you could actually send configurations to a network device from one management station
to the actual device itself have those configurations securely shielded by the SSH protocol.
Now one thing to note is the way SSH is going to be able to operate is that it's going to use
a technology we've already looked at within this very course and that is public key cryptography.
So again let's say we have server two here let's say we have server one here if these servers want
to communicate to each other in this secure manner what they're going to do is they're going to invoke
public key cryptography. Now you may recall when we talked about public key cryptography is that in
this architecture we're going to have both a public key as well as a corresponding private key. Now
the crucial thing to note here to really really remember is that the private key as it suggested
must remain private you do not want to share this with absolutely anyone at all whereas the public
key that is the absolute opposite this is very very liberal you can freely share this with
absolutely anyone you choose. So what this means is that both servers here can freely exchange their
public keys whilst keeping their private key absolutely private on the internal system and
because of that architecture that means that we can send messages to a server using that public key
which would therefore encrypt that message and can be subsequently decrypted by the private key
on the remote server we are talking to. So really no surprises here with respect to public or private
key cryptography this is something we have talked about before like I say understand that SSH is going
to implement this architecture but now what we want to do is to get a little bit more hands-on
and practical about what SSH can actually do for us the first thing that we're going to have to look
at are some configuration files and then we'll see some of the other things that we can use with SSH
like I say SSH allows us to provide a tunnel that is an encrypted tunnel whereby we can
shuttle data through that tunnel. Now you may recall that we have already talked about something
called FTP I believe that was in the very last skill well we can actually shuttle our FTP data
securely over an SSH tunnel that would be therefore called SFTP the secure file transfer protocol that
is again because we are wrapping this FTP connection within the SSH tunnel and this is again something
we will get to look at within this skill as well as something called secure copy scp again also
leveraging that secure SSH channel so we have a lot of stuff to get to within this skill the very
first time we're going to be looking at is a particular SSH configuration file and that's what
we're going to be talking about in the very next nuggets I hope this has been informative for you
and I'd like to thank you for viewing