Welcome. Cyberia 19. My name is Greg Stewart. Never subject matter expert for loans. Plus,
in this video, this part
five of module to we're gonna be covering an introduction to networking.
Now, most of you that they're taking this course. At this point in time, you should pretty much know about networking and believe some of the prerequisites for this course were six months of hands on Lenox experienced some networking experience.
You don't need to have six months of hands on. Let me experience to take this course. However, to take the exam, you should have
a good bit of hands on Lenny's experience
on and you know, you should have a good understanding of networking. Should understand the OS I model roast. I'll air
Well, it's a layers and understand how they work, how they function, interactive each other. You need to understand what packets are, what they do, how they're formed.
You should have a basic understanding of networking and how things are networked.
If you're using windows, you've had some experience with networking.
With your network, you're next. You're never gonna face cards,
know, installing them right, clicking and going to properties, figuring out the i p address selecting either D h c p. You're actually giving it a static address. Those are some things that were going to do and this put this part of the course.
So we're gonna focus on Lennox and of the different kinds of networking things. They're slightly different from Windows.
First off, we're gonna deal with some of the different files that would contain certain network settings.
So I'm gonna go ahead and long back into my machine here
and when the logs in will go full screen.
so we're back to our test machine here for cyber ery Sudbury admin,
and we're gonna do is we're gonna go ahead and open up the
And we're using a lot of love command line stuff from this portion of the course onward.
Well, we'll show some demonstration of some of the the gooey based network stuff in some of the gooey based file management file editing stuff. But we're basically fan of as a systems administrator with for Lennox, we're gonna be focused on
becoming a power user with the command lines. If you could do that, you'll have a great skill set. Your resume will be great. You'll be able to pretty much command any Lennox job you can if you really know your way around the Lenox spouses sneezing the command line
much quicker. And you can also begin developing scripts, paying on your language and
do everything automated, so it will be much easier. You'll have a great, really powerful skill set, so really try to focus on using the command line as much as you possibly can gain a good understanding of it. Understand? There's many cheat sheet websites out there that you can use to go out and see it much different commands have the use
how they're used, what they do. Have a working Sarah,
It's another we've launched. Our
MANNLEIN are terminal.
Let's look at a couple of the main files that will contain your network settings.
First off, not a file, but command. We've covered this couple times we could go to If
I have configure, I just call it if config.
This is basically the equivalent of I p config on your windows machine. So if configures we insure your interface configuration
here we have everything that are either and zero and our loop back address or look back in her face. So for Ethernet, zero over eat, eat zeros. Well, welcome Will refer to throw the rest of class. You can see it pulls a classy address is using D A. C p to pull down a address from an address from my router, my cable modem.
And you could see this. Classy. It's got the typical class even met and sudden that mask
and give you some information about packets dropped. Tell me Trent Pack has been transferred, etcetera.
So this is a great place to go for really quickly. If you need to get the I p address,
the broadcast address and that mask et cetera on the Mac address, it's there. So this is a good place to go. So you can see you have your hardware address here is gonna be actually your Mac address.
so, uh, that's the first place you could go for your basic network configuration items.
Another place you can go if you have.
If you don't have d n s involved in your network,
however you want to be able to resolve
I p addresses with names. Okay, This is what the U. S. Does
You can add host names to your host. File your resolve dot com filer, your brother of some other files. Let's go and look at those files.
the first file we're gonna talk about is the resolve dot com. Okay, this is gonna list your DNA servers for your Internet domain name resolution
and again for each of these files, there's actually man pages what we talked about man pages to show for short for manual. It's basically like a user manual for that command or for that file for that attribute clinics. So let's go to the file and look at the man page for so
it's ah, it's in slash etc. Slash result dot com.
So I'm gonna go there by doing seedy. Gonna change directory to slash Betsy and again on auto completing by hitting the tab Key
resolve. And this is actually spelled without the e on resolved comp.
And these are my is my fault, actually. Went back up here for a second. I'm gonna go to,
CD s a little list files, okay. And I'm gonna go to what I want to do since the file, It's not actually directory. It's a file. Okay, so within the etc director of the result that com file exists. So we want to actually go and open that file and read it
couple different ways. We can do that. We can use an editor. There's a couple of enters. There's the Nano editor.
There's the V I editor, the Vim editor. There's three different considers, but one I particularly use for the most part is Thievy I editor.
Everybody has their own opinion about which better they want to use some use Nano. They're all different
slightly and they all have different
means of navigating the file. But for this, for this, in this case, in this course, we're gonna use the V. I enter. So
and we'll talk about Well, I'll give you some examples. Different editors in the next module and Assistance Administration module module three.
We'll do some more file editing and do some again some more examples of different editors. But for now, I'm just gonna be focusing on using the P I editor.
So there's a couple ways that you can actually see the file on what's in it.
The quickest way and easiest way to do it would be used. The Catholics, the cat command. So it's just just like the animal cat. C A T.
What that's short for is contaminate. Then well, that's gonna do. Is going to give you a quick snapshot of the file contents on your screens. Gonna print it out and actually in the terminal.
Let's do cat. And then then type the name of a file, resolved
the cough, okay, and get out of completed. That's it. Auto completes a good way to make sure you're not making mistakes in spelling our case.
So I'm gonna do that, may enter, and it's going to give me the file content.
Okay, so you can see the hashtag or the pound character here is that is commenting out the lines. Okay,
um, don't at this have filed by hand. Your changes will be over it. So any time you make any changes to result dot com it's actually gonna
it's gonna fix is gonna be overwritten, Okay, So because it is pulling for D. N s, since we don't have DNA, since I don't have this intricate lab set up,
we don't have any D. N s here. But if you did have your dina server, you'd see it instead. Using search local domain
in the loop back address 1 27 011 for our name, sir. But we don't actually have a name server.
Currently, we don't have Dean s 2.2. So this is what you see now, if you did have d N s, you'd actually see the your d n. A server listed here. Your name server. Depending on your configuration and your networking architectural set up,
it's gonna be different for everybody. But this is basically where you're gonna see your d n. A server. Okay,
so now we've seen it with cat. We can catch a great command to use just quick and dirty. You can see the contents of the file. However you can't. We use in the cat command, you can actually edit anything. Can't make any changes to it.
To make changes, you've got to use an editor. So we're gonna use V I So I'm gonna do the same command, except I'm going to say V I
Sorry. Five finger in here,
Can I have a complete result? That calm
now It's just dropped me into an editor again. It's still giving me the same. You can see it. Show me the same
same exact file contents that you saw when I used the cat command. But instead, this is dropped me into an editor so I could go ahead and edit. It is not too edited by, you know, don't edit this file by hand.
Your chains will be over in. So I'm not actually, I'm not gonna give you a poor example, but actually editing a file says don't edit my hand. But this gives you an idea of what the V I does za file anger and opens up the file and allows you to edit it.
Since I don't wanna edit it, I'm gonna hit the escape key that's gonna drop me into a little record. Enter a command to leave, which always gonna type, huh?
I'm sorry. Escape the members, hype the colon
Hey, I didn't make any changes. The file. I'm just quitting
again. We're gonna talk more in depth about violating, will understand how we can edit it, and we'll use examples, create files, understand that. So I'm not gonna get into death on that. But that's a look at the result of com file Again. You would see that name, sir, over there
on DDE what it would look like if you had Deanna's involved.
So let's take a look at a different file.
This file is the etc host file again. It's in the etc. Director. Someone to stay in like I'm going to stay here in this directory. I'm just gonna do again cat
Okay. So again, cat Nate or the cat command,
it's just printing a quick and dirty look at the snapshot of the file content.
So here you can see again If I had different hosts if I wanted to create a different VM on my network
and given a name of cyberia Lennox bm underscore too
admin d m that I could actually
put that in here instead of actually, instead of having to pee in the eye with the I p address, I could just paying the machine name.
So this is nice to set up. You don't have d N s, but you wanna get away from having to use the I p address for everything.
All you have to do is place all of your host inside of the host file, and it will do that. So
there is one thing that you need to remember when you're doing
when you're when you're creating stuff with your host file, there's no persistency involved with your host file. Okay,
So what means what persistency means is that if I'm going to place host file host names in my host, etc. Host file
when I go to reboot, what if I have to reboot or the machine goes down? For some reason, when I come back up, that host files gonna be blank.
It does not hold onto any changes that are made to it. So it's just a running change, Okay,
not the greatest place to do that. But when you do that you created there, then you also add the hosts
network sis config file or your dad or your resolve dot com file. Or, if you have Deena's, that's where it will stick.
But to be quick and dirty. If you're just upper running, you want to make sure that you can ping things with the names or you wanna add it. So it's etc hosts. And again, if I do, the I
draws me into the file editor. And here's where I can actually make any changes at
So let's go ahead and add. But the host just to make believe, though, so you can see what the editor will. D'oh.
So in order to get into the motor, I'm actually going to start editing the file. I have to hit a lower case I
input mode, so I'm actually gonna start making input. You can see it the bottom. When I hit, I tells me warning. I'm changing a read only file. Okay. Again, we're gonna cover all this inside of the file editing portion of module three. It's a Sandman Martin module. So just for now, I'm gonna show you what change will be made. I could do this type
No. Blow hit, enter.
okay. And save those changes when I'm done with my editing mode or input Mohit escape. That takes me out of it anymore. I can't type anything else. We'll see if I start typing things. Nothing happens
Now, if I go up here and I do a d d it deletes the entire line. Okay? Begin Will cover this in death, so don't worry about it.
But I want to get out of here. I'm just gonna type command, and I'm gonna excite quick.
Okay? This is no right since last change. And
ah, bang or exclamation and Lennox, we call exclamation marks, bangs
and a bang to override. Okay, so there's no right since last. I'm not. It's not gonna want me to make you the rights for saves to this file because it's Marie only.
So again, I have to do escape,
and do a quit with the bang, and it'll let me go out.
Okay? Normally, if it wasn't a read only file and it was editable, I hit the quick
hit the colon, and then a cue for quit to get out. It would tell me you've made some changes. Do you want to save this? Or the last rites have not been saved yet.
Then you have to do a w Q right, and then quit. So you do a right quit and then a bang to force the right quick. And then you get out on you. Major city. You Major, save your changes to that file. So some good stuff. So good files again. Just using cat will just drop you into the file contents on your screen. Easy. Good to go.
So another another file that we're going to look at
uh, in this switch dot cough. Let's look at that one again. I'm used the cat command can cat short Furkan, Captain eight.
You know, take. It s
So this is basically ah, the configuration here. This is an example configuration of the new
names, service switch functionality. And this has to do with Dean s. Okay.
It's gonna list the order of host name search. Typically, typically look at files.
been been Miss server than D n a server. And you know you could do that here.
It's all here for you in this file. Easy to do is you Look at it again. You get edit this files. Well,
now there's other files that air not pertinent to Bunty.
And those files are the pet ceases config network, and I'm actually gonna pull up a text editor
take these out for you, so you can see. And it's well, actually, no. In fact, I'm just gonna go here.
Just go here and do a
You're some other files. Will type amount for you here so you can actually write that down
were sent us all pretty much in the same family.
You're gonna see these files Also. These are the files that you're not going to see in a bun too.
And this is going to specify your network configuration. For example, your static I p your D a c p your nous, et cetera. This is where you're gonna see those items. Okay?
Another files going to be the etc.
if C f g and then your device name.
This is gonna be specifying your TCP network information.
It's gonna show you your interface configurations
for your devices for zero each one. Look back. Hello? Whatever. Devices that you have for networking the three and see the that information. Okay.
And then one other one other look and I'll just keep this over here. So you can, uh,
if you want to take time to jot it down or whatever,
or if you're using Ah, different destro for using destro Such a sendoff door, Red hat. You can actually try these out in your own head here or your own terminal.
I'm gonna open up the sea, uh,
CD into the network.
Looks like this director doesn't exist here in this.
No, no, no network. There it is.
Okay, to see into that
okay. And interface is someone to cat to face. This
shows me my interface is right. So it's showing me here the auto for Luke back interfaces that are usually enter. This is my Etsy network interfaces. So there's those were the files that you're most commonly gonna be looking at for a networking.
So a couple of networking commands. Let me just show you a quick command. It'll help you start to get kind of cluttered in your terminal. Sometimes I
we get a little crazy when it comes to terminal stuff, trying to keep it clean and neat. But when I see this, it's kind of jumbled and I get kind of distracted by all the different commands. A color. So I'm just going to have a clear
and that clears out the terminal window, takes you back to a clean,
clean state where you can see that there's nothing there. Okay,
so in order in order to
do some other commands of my mom listed here for a walk through the 1st 1 of the most common, I'm gonna go back to, um, we go back a couple of levels.
I'm gonna go here back to my beauty,
come back to route, and I'm gonna type in
And that command will just give me my host name. This tells me the name of the
computer virtual machine, et cetera, that I'm on currently. Okay,
Now, if I do a host name, this most likely is not gonna work. I'll tell you why. In just seconds,
If I do a host named Dash D, this is going to give me my domain. The name of my domain. Well, since this is a stand alone box and I don't have any domain currently built out, it's not going to show me anything However, if I did have a domain and for instance, it was named
it would actually show me the name of the
It was Show me cyber dot Local is my domain. Okay?
Same with the command of host name Dash.
that's gonna be is showing me the name of the VM once again. But is this would show me if I had a domain this to show me the fully qualified domain name for the machine. Okay.
And then host name. That's another good one. Dash, I
gives me this is showing me my look back address, but this is basically look back for the
Okay, so this is there a couple of the couple quick commands that you can use? All right,
now again, Back to if config if config.
Okay, so if configures a great one because we talked about this earlier, gives you your i p address. What are some other things? You can do it if traffic
right. So I can actually create an interface. I can bring interface up. I could take a interface down
if I want to take an interface down. I type if
Again. Failed. Strung. This is Lucy for to do with studio.
Ignoring unknown interface easier. Okay, so it's already up, so it's not gonna
kind of important. Well, it's already up. It's not gonna do anything. If I was doing if down zero,
you would actually take the interface down on what would happen if the interface down, Well,
we'd be disconnected from the virtual machine because we just shut down the interface, the network interface.
So I'm not gonna actually do that. But that's what you would do if you wanted to get the interface up or down. You would actually use that Thio do that. Okay,
so you can do that. You can also
actually configure the interface by using the config command.
So if configures a powerful command and I'm actually gonna clear this out against you, see a better running view.
So usually the if config man Schiff
So that if convicted man resides in the ESPN
directory, Okay, So, in order to use that director and we do already use this command better, we need to be We should have. We should be in this directory. Sometimes it'll let us. We'll go ahead and try it first and see, but less. But well you want to do is tight if config.
Your I P address was 1 68 0 10 I'm just using an arbitrary I p address. Just a show. An example. I'm not actually gonna configure it.
Next. You want to give it till tell the machine that you're going to give the next net mask coming up next would be for a classy to 55 0
and you won't tell the broadcast address, which would be, you know, networking be the last
right after the last usable rights, which had been a classy, which would actually be 2 55 So forethought, that would be 2 to 5.
Okay, then you hit Enter. And what that's gonna do is actually going to configure eat zero
to have this dress. Okay,
so we're not we're not actually gonna do that because we don't wanna miss it in fear are our interface.
So that's what you want to do. Okay, So you want you can do that and it will actually configure it. So there's different
interfaces. If there's an each one e 33 accessory 4th 5 actually configure each of those with a different I p address depending on where you're using a machine for
those are those are really helpful if convict man is really helpful.
And again, you know, some of the commands you can type in for if if config. All right about here
zero and realized. Now I put the wrong commander.
Originally, I typed in just
if, uh, this is wrong.
So it's actually a full command If config been your interface.
I'm not just Yeah. Then your interface. And I'm gonna type these in here. So, you know, this is just where you going in, Put something
okay? And then you're
your type. What? You want to do your option up?
Okay. And then you're in the best would join us. He hit. That in turn, takes about
adversely. If configured in your interface
another command, you can uses nets. That
And what does nets dad do? Well, if you remember, if you've done this with windows, it's fairly the same is pretty much the same thing, right? It's gonna tell you what you're
You know what? You're what you're doing. What you're seeing Come across your for traffic. Okay,
So what you want to do? It's just type. And we're going back here to the command line.
I think this is telling me everything that's connected. What is doing? What it's listening on.
there's different options you can do. Is telling your routes, et cetera, what you want to do? It is controlled by first. But every move just one over falling. So you type in the command and you have to type in the actual argument.
It's gonna be a tool. It's gonna display your network connections both your incoming and outgoing. It's also gonna display your route tables
and other network interface and network protocols statistics. Okay,
so it's also it's also it's it's available on Lennox and UNIX, but it's also available on Windows. What we want to do for net stat. If you want to be a little bit more granular about it
is let's just let's just display table of all our network interface. It's kay.
So what we want to do for ness that back man and let me clear the cell
that's giving me my interfaces occur. I, like currently only have to interface is my eat zero, which my Ethernet connection to the Internet
and then my lube back. Hello? It's my lube back, Luke. Back address, which is not Obviously it's not giving me anything.
Um, and then another another
the commander argument that we can use this for routes. We can do that, stat.
This is gonna tell me my routes. Okay? You're not seeing a whole lot because I'm using a fairly simple insulation.
Okay, let's look at some others
statistics. We could see the statistics from each of the protocol each the protocols. That stat.
Well, this gives me my eyes. Just so I've got UDP statistics for UDP. Stroll up a little bit.
and you're just a bunch of different ones, right?
So what I could also look at is the user's right
leave its users. Yeah,
Okay. So, miss, That's also it's a very powerful tool that you can use. All right. It'll help you understand what's coming across your network. On what interface? What protocols it's using.
You know, if It's listening. It's not listening. What is listening on etcetera? So good tool to use That's that is good for network.
So what's another command? You think any other other network commands that might be helpful in this situation?
Obviously, that was there, and we're face to face. You could be able to shout out some answers.
Let's jump into it. So another command that would be very helpful is the Ping Command. What is Ping? Duping is pretty much the most simple networking command you can give.
Ping is valid for Windows and UNIX Lennox and it pretty much all of those, right? So what it is is using the I, C and P Protocol
to reach out and check to see if a target that you're pointing at is actually alive and it will respond back to you.
So since I'm connected to the Internet, I can actually go ahead and pink something that will try us unless I'm just going to use google dot com is an example of
and I'm getting a response. ***.
See that? I'm getting 64 bites, which is my pink packet.
I'm getting it back from I P address 74 1 25 to 27
timeto live packets from the packet is 128 seconds.
Thank you. And it is going to keep continuously continuously pinging. Or you can see here is I've actually got a lag
of 42 milliseconds. It's much fairly high for ah, for home user. Should be should be much less than that.
But you want to be. You want to try to be around somewhere on 20 milliseconds because of Peking packets, Not that large. Imagine if you were sending a video or trying to upload a video to YouTube or something. Your flag would be much larger if it was ah ping of 42 milliseconds.
Okay, so it will just keep going much like windows. When I type in peeing the i P address in a space and a dash T that's a terminal ping. That's just gonna keep going until I stop it. We'll let X on the map. It just keeps going until you actually kill it with a control C, which is just did.
They will tell me that 68 packets were transmitted zero packet loss and the time that it took.
Okay, So I could do that. I can also use a command. It's commonly used in windows, which is in its look up.
Look up and it's Look up google dot com
again? This is s lookups, his name server lookups Gonna tell me all of Google's name servers and you can see they're all listed here. All the i P addresses,
etcetera. Great tool. The have great tool to use when you're trying to figure out what I P addresses Tash to what name With Indian s
one of the best tools you can use in this system administrator when he comes to networking,
Another great tool that I love to use when I'm trying to figure out kind of what my experiencing big time, late and see. And I'll understand
kind of what my my hops are our routes looking like for someone in point to another,
I can use the command that will allow me to do that
is trace row tracer. Okay,
so what I want to do
is into the trace route command.
That's gonna be a trace route.
And I'm going to enter Where I wanted to go, So I'm gonna use google dot com again.
I'm sorry. Could tell me is I've got it installed. So let's let's going still trace around.
Okay, so it's going ahead and go install it for me installed.
So now I want to use which,
which trace Rome will tell me where it's located. User been so it should allow me to just launched here about being in that directory.
So when do you again trace route
Okay, it's working. What it does is kicking off is gonna show me how many hops it takes to get to where I'm going.
So it's going, It's thinking about it.
As you can see, it's telling me the middle seconds that showed me in my my my original address, which looks like it's probably my gateway.
Well, 91 68 200 out, too. And it's going to 74 1 25 to 27 to 26.
it's gonna go is because this is 30 hops, Max. You could see this here, right? It timed out of 30 hops. Max
Chlo, 30 hops. Max is just gonna take 30 hops until you know, at 30 hops gonna go ahead and kill the trace route, but so it's taking a long time. There's a little bit of network late and see involved there
Should it should have actually gone away. But my my max hop, I had this set to 30 so that's fine. But this is how you can do it and a networked environment, an enterprise areas solution. Architecture
If you just want test how long it takes you to get to your What kind of latents here, what kind of hops you have to get from a user desktop or an admin desktop
back to the domain controller. You can do that and you'll see that it will show you exactly where you're going
or to actual Web site that you're trying to get to. You may have some late and seeing getting to a website. Will shamba hops you're taking? We'll try. One more is to see if it's any different. Here.
See, that's let's see if this is any different
again. With my my heart, you're 30. Max hop
looks like it's probably going into being the same.
Okay, well, I'm gonna do is I'm gonna try one just for grins on my home network.
Trace round made to 1 68 0 11
We'll see if I can pick first
camping it. Let's Ping.
Yeah, we can't be now you.
So what we would do is he would use trace route and in the i p address or the fully qualified domain name where you want to go and I will tell you you know how he hops it takes to get there.
so we looked at in s look up. We looked at,
um, looked in this look up and we looked a trace route. We looked Ping If config
I'm here again is some of the files that we looked at that you can find on Red Hatter fedora sent toss for utilizing the files That could tell you your network configuration.
Look what the cat command, It'll show us, we'll have her have it. Prints it out on the screen. There's some really good options because good things. I hope you understand. Basic introduction. Thio Lennox Networking again. If you look at this from a gooey perspective, I'm gonna go here to my little networking right
or I could just go here to my search for that type of networking.
let's see what this brings up. Brings up my network. Settings that were a proxy Don't have a proxy set, but I could do one if I wanted.
My wired connection tells me my address, My default route, which is my default gateway
and D N s. Which isn't it being my gateways world?
Okay, good. All settings
takes me back out or I can go to
that Were connections.
That shows me one network connections. I got one that I have one that network connection at the time
currently. But I could go to credit that if I want to give it a name,
you can do whatever I want here, Okay? And this doesn't meet with general security settings. I p B B four settings
currently said the GP, I could give it a static or in a linen. Static is referred to as manual, so I could do manual Oregon to static or just disable interface altogether.
If I do that, I'm gonna lose my virtual machine because I'm killing the network, and that's I depend on the networks can't my virtual machine.
So I'm gonna go ahead and close that out.
So those were some of your basic. This is introduction to networking.
This is your basic networking items. Some of the files that you can look at
and a CZ. We get into the system administration portion of the course in the module three. We'll see some more examples of networking how we can troubleshoot it, have been set it up a little bit better
and give you a better idea and understanding of a little more advanced networking topics.
But for now, you should be able to in your own Lennox Destro there that you have downloaded and installed.
You should be able to try to try out some of these files and navigate some of the files. Check him out, try some of the commands, try trace around duping, maybe build a couple of virtual machines and see if you can ping around the virtual machines and
use your host file to set up the names. If you don't have D N s, you can add the host names to your host file and then you can actually paying with the host name.
So this is your introduction in Lenox networking
and should be a good start for you, and we'll talk more about it in the Systems Administration module. Of course,
we'll talk about the meat of it, so thanks for watching. Hopefully, this was easy for you to understand, and now you can go ahead and try and implement your absolution.