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Hey everyone and welcome back. So what we're going to focus in on in this skill right here

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is all about SSH that is Secure Shell. Now we do have some familiarity with Secure Shell

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of course but in this skill right here we're going to look at the details of the connections

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in a little bit more detail. So with that said how about we dive on and then so the

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very first thing that you should know about SSH is that this is something we use for remote

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connection. So this is remote access we're dealing with here. Now technically you can

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just SSH back into your local system but realistically we're talking about making a connection to

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a different computer to a different network that type of thing and the big thing here is

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that SSH as the name does imply is indeed secure because before we actually had SSH we had

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this RETCHID technology I would say at least now called Telnet. Now Telnet perhaps I'm

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being a little bit unfair. Telnet did provide a good service it allowed us to have remote

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connectivity but the reality is Telnet was unencrypted. Now in today's day and age we

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know that we can't deal with these unencrypted connections because quite simply they are

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just nowhere near secure enough you are just inviting trouble into your network and depending

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on the actual industry in which you are in potentially opening yourself up to accusations

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of malpractice and potentially litigation so really you want to have your security in

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order. So one of the best things that you can do for security as you may know is to

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invoke encryption and that is what SSH was all about. So really what we have here is

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we have a server this can be called server one again because as we know by now I'm just

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so creative and we could have over here let's just call this you guessed it server two.

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If server one wants to log in to server two all we do is we set up this type of tunnel

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and this tunnel is going to be an SSH tunnel. Now once we open this up you can visualize

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this as like an encrypted pipe so that means that you can actually send information through

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this channel and all the data here is going to be protected by the outer layers of the

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SSH tunnel. So you could actually send configurations to a network device from one management station

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to the actual device itself have those configurations securely shielded by the SSH protocol.

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Now one thing to note is the way SSH is going to be able to operate is that it's going to use

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a technology we've already looked at within this very course and that is public key cryptography.

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So again let's say we have server two here let's say we have server one here if these servers want

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to communicate to each other in this secure manner what they're going to do is they're going to invoke

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public key cryptography. Now you may recall when we talked about public key cryptography is that in

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this architecture we're going to have both a public key as well as a corresponding private key. Now

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the crucial thing to note here to really really remember is that the private key as it suggested

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must remain private you do not want to share this with absolutely anyone at all whereas the public

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key that is the absolute opposite this is very very liberal you can freely share this with

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absolutely anyone you choose. So what this means is that both servers here can freely exchange their

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public keys whilst keeping their private key absolutely private on the internal system and

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because of that architecture that means that we can send messages to a server using that public key

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which would therefore encrypt that message and can be subsequently decrypted by the private key

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on the remote server we are talking to. So really no surprises here with respect to public or private

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key cryptography this is something we have talked about before like I say understand that SSH is going

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to implement this architecture but now what we want to do is to get a little bit more hands-on

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and practical about what SSH can actually do for us the first thing that we're going to have to look

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at are some configuration files and then we'll see some of the other things that we can use with SSH

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like I say SSH allows us to provide a tunnel that is an encrypted tunnel whereby we can

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shuttle data through that tunnel. Now you may recall that we have already talked about something

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called FTP I believe that was in the very last skill well we can actually shuttle our FTP data

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securely over an SSH tunnel that would be therefore called SFTP the secure file transfer protocol that

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is again because we are wrapping this FTP connection within the SSH tunnel and this is again something

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we will get to look at within this skill as well as something called secure copy scp again also

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leveraging that secure SSH channel so we have a lot of stuff to get to within this skill the very

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first time we're going to be looking at is a particular SSH configuration file and that's what

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we're going to be talking about in the very next nuggets I hope this has been informative for you

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and I'd like to thank you for viewing