Time
31 hours 29 minutes
Difficulty
Beginner
CEU/CPE
30

Video Description

Port Communication Endpoints This lesson covers ports which are communication end points. Ports allow for multiple applications to use net connections and are reserved by programs and applications. The defaults can be changed. Ports communicate over TCP/UDP and are part of the Transport Layer) layer 4 of the OSI model.

Video Transcription

00:04
before we get into our next big set of protocols, we need to understand a concept called ports
00:11
Now ports our communications in points for our connections to our computer.
00:17
So
00:19
if you know what a port is for a say, a carport or a port that a ship stops in tow, unload, unload cargo, then
00:29
you can sort of use that mindset when we're thinking about computer ports there a logical in point for data or communications to unload onto our computer.
00:39
Ports are commonly shone as if we're riding out a port.
00:44
We have our I p address, so we'll put 1 92.1 68 that 1.13
00:51
and they won't have a colon
00:55
and then a port number so we can have port 80. That's where the port number looks like.
01:00
Colon 80.
01:03
So why do we have port numbers? Why don't we attack those on onto the end of our I P addresses? Well, a port number essentially allows us to have multiple applications and multiple different programs and multiple different protocols connecting to our computer at once.
01:21
If we just had our one I p address with one port and we were receiving multiple different data connections at once. It would be harder for our computer to logically be able to say, OK, this is this protocol. This goes here. This goes here and separate all those out into different programs and applications.
01:38
So we need to have multiple different in points for all of our ports to be able to connect for all of our data streams to be able to connect to.
01:45
So that's why we have multiple ports. It allows us to have multiple applications on multiple data streams going over one network connection so we don't have to have
01:56
6500 wires going into the back of our computer, and there are speaking of 6500. There are 65,535 ports available per connection.
02:09
Now,
02:10
those summer a lot of those ports have protocols research associate ID by default with certain ports. For example, Port 80 is by default.
02:22
Http, an http is how we transform transmit Web page information.
02:28
So if you load a Web page, if you go online, type in google dot com and it brings up Google. That data is being transmitted by default to your port 80.
02:38
So you're sending a data packet out of your port 80
02:44
and then when your data is coming back in, it's going to 1 92.1 68 That one about 13. Port 80.
02:53
So
02:53
because port 80 is the default report for http, that's where it's gonna go. Unless we otherwise specified
03:00
now, these defaults can be changed.
03:04
If you set up a I P camera in your home, you may have a Web log in page for that I p camera. That is not Port 80.
03:13
But if you were to go to http
03:16
and then the i p address of your your i p camera, it wouldn't live the page. And you say, Well, why why isn't it lot not loading the page? This is the right address. Well, for security reasons for security by obscurity, they may have changed that default port and said, OK,
03:36
this I p camera, its web interface is only able to be reached on 1 92.1 68 not 1.13 point
03:46
80
03:46
33.
03:50
So that's within our 65,000 port number range. So in order to navigate to that interface. For that I p camera, you would have to go to
03:59
h T T P
04:02
colon forward slash forward slash 1 92.1 68.1 dot 13 Port 80 83.
04:10
If you didn't include that,
04:12
if you didn't include your port 80 33
04:15
your browser would go. Oh,
04:17
this is an http connection
04:20
mine default port for http is Port 80.
04:24
So I'm gonna attack on Port 80
04:28
and I'm gonna try to communicate with Port 80 with this device. And then when it gets to that device, when it gets to this I p address and it tries to initiate a connection with Port 80 is denied.
04:36
It's blocked that port 80 is closed and it says, Well, wait a second.
04:42
I'm supposed to be delivering a package here. I guess this is offline. I guess I can't deliver anything here. I guess there's no Web interface,
04:47
but that default port has been changed. Instead, support
04:51
80 33. So we need to know that we also need to know that just changing port numbers isn't a
04:59
catch all security measure.
05:00
We can't just change the different ports for our different protocols. and say, OK, um,
05:05
I don't need to have I don't need tohave secure file transfer protocol. I don't need to have f t p s. I don't need to have file transfer protocol secure. I can just transfer over standard FTP standard file transfer protocol where I can just transfer over trivial F T p a t f t p protocol
05:24
unencrypted file transfer protocol. And it's okay, because I'm just gonna change the default port.
05:29
Well,
05:30
that might be all great. Jolly for all of about five minutes until someone with a port scanner just says,
05:39
I know they're transmitting files,
05:41
cause this is business. I know this servers and FTP server, but I'm not seeing the standard ftp port open.
05:47
So let me just set up my port scanner, and I'm just gonna have it tryto contact
05:54
every port from 1 to 65,533
05:58
535.
06:00
And then when it hits whatever port you set up as your default is, you change to your t f T P point. It's going to say, Oh, there it is. And then it's going to start
06:10
viewing that information, viewing that data
06:13
so
06:14
we need to understand that the defaults can be changed. It can be changed as an additional layer of security for security by of security. But it should not ever be our only layer of security We don't. We don't protect our confidential files by
06:32
creating ah 100 directories and making amaze with our file folders
06:36
in order to hide our files and make them secure. That's not how that works. We can use a search and then find where the file is in those folders.
06:45
We don't hide our WiFi past. We don't protect our wireless by taking our WiFi and simply disabling S S I d broadcast. People can find that. And then they could just connect to our wireless. We need tohave files encrypted, and we need to have our wireless
07:03
set with a
07:04
W p. A to password.
07:08
Same thing with our ports. We don't just protect our protocols and we don't protect our servers just by changing the default port numbers for the different protocols were running.
07:15
So
07:17
all of the communications and all of the different protocols which have in points that our ports are going to be communicating over either TCP or UDP
07:29
all of our different protocols which are communicating to ports need to have some sort of communication protocol to deliver that data.
07:36
We talked about some of our other protocols which don't work with ports, But these protocols have data packets to deliver.
07:45
They need to have a logical place. Think of them as ships. They need to have a logical place to stop at our country at our I p address and need to have a place that they can unload the packets
07:58
and they need to have some sort of shipping company. They need to have some sort of communications protocol,
08:03
either TCP or UDP, to determine how they're going to package that data, how they're going to segment those packets and if they're going to, if we're going to have a connection based or connection less protocol, other TCP or UDP so we'll be discussing our different protocols.
08:20
We'll be discussing our different protocols, and when we do,
08:22
will be discussing either t c p R u D P, as well as the port number that they're associated with.
08:28
It's very good, too.
08:31
Learned default port numbers for popular protocols because if you're analyzing network data or you're analyzing traffic, you'll see those port numbers popping up and you'll be able to say,
08:43
Okay, this protocol is trying to go here. This program's trying to access here.
08:48
Why is this program trying to access here? This program shouldn't be doing that. Or why is this data trying to access here? Or if we see certain sequences of ports being hit on our firewall, we can recognise very quickly. Oh, this shouldn't be hitting this port or this port or this port. So
09:07
it's very important to learn default ports and protocols for popular for popular protocols so that we have them in our mental tool kit to use and not have to be constantly carrying a chart around. And when you go into a test, they're not gonna let you carry a chart into a test. So you need thio. Only charge you're gonna be able to carry is the one that you've already memorized in your head
09:26
for which protocols go with which ports.
09:28
So
09:30
enough said about that, um lastly, our ports, they're going to be at our transport layer layer four. We mentioned how our ports are related with T, C, P and U T P layer four is our transport layer. Where are TCP and UDP live, where TCP and UDP package up a packet segment on packets up and begin to
09:48
set up communications with other in points?
09:52
And so our ports are also going to be at the transport layer because it's going to be the transport location where we send packets from and where we receive packets, too. So just remember our ports, our communications in points. We have 65,535
10:11
ports per I p address ports per connection.
10:13
We default. Ports can be changed. Communications of TCP or UDP transport layer four and a port
10:22
looks like this
10:26
1 92 that one succeeded. That one about 13 is an R i P address with colon meaning port number,
10:33
whichever port number we have.

Up Next

CompTIA Network+

This CompTIA Network+ certification training provides you with the knowledge to begin a career in network administration. This online course teaches the skills needed to create, configure, manage, and troubleshoot wireless and wired networks.

Instructed By

Instructor Profile Image
Anthony Harris
Systems Analyst and Administrator at SAIC
Instructor