Understanding Protocols, Ports and Sockets | Intro to Computer Networks Course Preview

Summary

This video delves into the fundamentals of network protocols, ports, and sockets, essential for data exchange between computers. It explains how protocols like FTP, HTTP, and DNS operate on specific port numbers to ensure proper communication. The presenter uses a Windows Server 2016 environment to demonstrate identifying active protocols and services, such as IIS, DHCP, and DNS, and clarifies the concept of sockets by combining IP addresses with port numbers. The video also touches on the types of ports, including well-known, registered, and dynamic ports, and their roles in differentiating multiple services running on a single server.

Takeaways

• 📜 Protocols are the rules that govern how data is exchanged between computers in a network, ensuring effective communication.
• 🔍 Network protocols are often implemented as processes or services on operating systems, such as DNS, DHCP, and web servers.
• 🔑 Ports are logical constructs associated with protocols, each with a specific number, to differentiate the services running on a computer.
• 🔌 Sockets combine an IP address with a port number, forming a communication endpoint for network services.
• 🖥️ A computer can run multiple protocols simultaneously, and ports help to distinguish between them, like FTP on port 21, HTTP on port 80, and DNS on port 53.
• 📈 There are three types of ports: well-known ports (0-1023), registered ports (1024-49151), and dynamic ports (49152-65535).
• 🌐 Well-known ports are assigned to widely recognized protocols, while registered ports can be requested for less common protocols.
• 🔄 Dynamic ports are used for temporary communication needs when connecting to servers to request information or data.
• 💻 The Windows Server 2016 operating system was used in the video to demonstrate how to identify running protocols, ports, and services.
• 🛠️ Tools like Task Manager, netstat, and netstart can be used to view active network services and their associated ports and processes on Windows Server.
• 🔗 The demonstration showed how to use a web browser to access services running on specific ports, highlighting the role of sockets in network communication.

Q & A

What are protocols in the context of computer networking?

Protocols are rules that dictate how data is exchanged between machines in a computer network, allowing them to communicate effectively using networking protocols.

How can you identify protocols running on a Windows Server 2016?

You can identify protocols running on Windows Server 2016 by looking at the processes and services tab in Task Manager or by using command line tools like 'netstat' and 'netstart'.

What is the difference between a physical port and a logical port?

A physical port, like a USB or RJ45 port, is a hardware interface on a device. A logical port, on the other hand, is a number associated with a protocol to facilitate communication between networked devices.

What is a socket in computer networking?

A socket is a combination of an IP address and a port number that identifies a specific process or service on a network, allowing for communication between networked devices.

Why are port numbers necessary in network communication?

Port numbers are necessary to differentiate between multiple protocols running on the same computer, allowing the system to identify and route data to the correct service or application.

What are the three types of port numbers?

The three types of port numbers are well-known ports (0-1023), registered ports (1024-49151), and dynamic ports (49152-65535).

What is the default port number for HTTP?

The default port number for HTTP is 80.

What is the purpose of DHCP in a network?

DHCP (Dynamic Host Configuration Protocol) is used to automatically assign IP addresses and other network configuration information to devices on a network.

What is the purpose of DNS in a network?

DNS (Domain Name System) is used to translate domain names into IP addresses, allowing users to access websites using human-readable names instead of numerical IP addresses.

How can you demonstrate a socket in action using a web browser?

You can demonstrate a socket in action by entering the IP address of a web server followed by a port number (e.g., http://192.168.1.1:80) in a web browser, which will attempt to connect to the server on that specific port.

What does the 'netstat' command show in Windows Server 2016?

The 'netstat' command shows the status of active connections, including the IP address, port number, and the associated Windows process ID for each connection.

Outlines

00:00

🌐 Understanding Protocols, Ports, and Sockets

This paragraph introduces the concepts of protocols, ports, and sockets in the context of computer networking. Protocols are defined as rules governing data exchange between machines, with network protocols being essential for effective communication. The video uses a Windows Server 2016 virtual machine as an example to demonstrate identifying processes and services related to protocols. The paragraph explains that each protocol is associated with a port number, which is a logical construct rather than a physical one. The combination of an IP address and a port number forms a socket, which is crucial for differentiating between multiple protocols running simultaneously on a single machine. The need for ports and sockets is emphasized, as they allow a computer to manage multiple network applications at once.

05:01

🔌 Exploring Port Types and Their Functions

The second paragraph delves into the different types of ports and their functions. It outlines three categories of ports: well-known ports (0-1023), registered ports (1024-49151), and dynamic ports (49152-65535). Well-known ports are assigned to commonly used protocols, while registered ports are for less commonly used protocols that organizations can register. Dynamic ports are used by clients when connecting to servers for data requests. The paragraph also mentions that the video will cover popular protocols and their associated port numbers, using TCP or UDP, and provides a table for reference. The focus is on giving viewers an understanding of the variety of protocols and their port numbers.

10:03

🖥️ Demonstrating Protocols and Services on Windows Server

In this paragraph, the speaker provides a live demonstration on a Windows Server 2016 machine to show how protocols, ports, and services can be identified within an operating system. The speaker has installed DHCP, DNS, and a web server (IIS) on the virtual machine to illustrate this. The paragraph explains that while viewers don't need to know the specifics of the setup, the demonstration aims to show the basics of identifying these components in an OS. The speaker uses Task Manager to show processes and services, and then moves on to using command-line tools like 'netstat' and 'net start' to provide different views of running services. The demonstration includes showing how to find the web server running on port 80 and DNS on port 53, and also attempts to access an unconfigured HTTPS port (443) to show the difference.

15:04

📚 Conclusion and Call to Action

The final paragraph concludes the video by summarizing the content covered and encouraging viewer interaction. The speaker invites questions about the topics discussed, such as protocols, ports, and sockets, and how they were demonstrated on the Windows Server 2016 machine. There's also a call to action for viewers to like the video, subscribe to the channel, and check out the course mentioned in the video description for further learning opportunities. The speaker expresses appreciation for the viewers' time and looks forward to their presence in future videos.

Keywords

💡Protocol

A protocol in the context of the video refers to a set of rules that govern data exchange and communication between computers. It's fundamental to networking, ensuring that data is transmitted and received in a consistent and predictable manner. The video emphasizes the importance of protocols by explaining that they are the backbone of how machines communicate effectively, with networking protocols being the specific rules for such exchanges.

💡Port

A port, as discussed in the video, is a logical construct used in networking to differentiate between multiple services running on a single device. Each protocol is associated with a port number, which helps in routing the correct data to the appropriate service. The video clarifies that ports are not physical like USB or RJ45 ports, but rather numerical identifiers that are crucial for network communication, such as FTP on port 21 or HTTP on port 80.

💡Socket

A socket in the video is defined as a combination of an IP address and a port number, forming a unique endpoint for sending and receiving data. It's a fundamental concept in network programming, allowing for the establishment of connections between two networked devices. The video demonstrates how sockets work by showing an IP address bound to a port, illustrating how data is directed to specific services on a server.

💡Well-known Ports

Well-known ports are a range of port numbers from 0 to 1023, which are assigned to commonly used protocols. These ports are standardized and recognized across the internet to ensure that common services are easily accessible. The video mentions well-known ports as part of the explanation of port types, emphasizing their importance in network communication.

💡Registered Ports

Registered ports, as explained in the video, are a range of port numbers from 1024 to 49151. These ports are assigned to protocols that are not as universally recognized as those on well-known ports but are still standardized. They are often used for services developed by organizations that require a standardized port number for their applications.

💡Dynamic Ports

Dynamic ports, according to the video, are port numbers ranging from 49152 to 65535. These are not pre-assigned to specific services and are instead used dynamically as needed by applications. When a client requests data from a server, it might use a dynamic port to establish a temporary connection. The video highlights the flexibility and utility of dynamic ports in network communication.

💡IP Address

An IP address is a numerical label assigned to devices connected to a network that allows them to communicate with each other. In the video, it is mentioned in the context of creating a socket, where an IP address combined with a port number uniquely identifies a service on a network. The video uses the example of an IP address 192.168.1.1 bound to port 80 to demonstrate a socket.

💡DNS (Domain Name System)

DNS, as discussed in the video, is a service that translates human-readable domain names into IP addresses that computers use to identify each other on the network. It's a critical component of internet infrastructure. The video mentions setting up a DNS server on a Windows Server 2016 machine, showing how DNS services can be identified and managed.

💡DHCP (Dynamic Host Configuration Protocol)

DHCP is a network protocol used to automatically assign IP addresses to devices on a network. The video explains that DHCP is important for managing IP addresses dynamically, ensuring that no two devices on the same network have the same IP address. The video also mentions the ports associated with DHCP, which are 67 and 68.

💡IIS (Internet Information Services)

IIS is a web server software used to host websites and web applications. In the video, the presenter demonstrates how to identify IIS running as a service on a Windows Server 2016 machine. IIS is an example of a service that uses a specific port (port 80 for HTTP) to serve web content, illustrating the practical application of protocols and ports.

Highlights

Introduction to the concept of protocols as rules governing data exchange between machines in computer networks.

Explanation of network protocols as essential for effective communication between computers.

Demonstration of identifying network protocols as processes or services on a Windows Server 2016.

Clarification on the difference between physical ports and logical ports in the context of network protocols.

Description of how each protocol has a unique port number for identification.

Introduction to the concept of a socket, which combines an IP address with a port number.

Reasoning behind the necessity of ports and sockets for differentiating multiple protocols running on a single computer.

Example given of a server running FTP, HTTP, and DNS services on different port numbers.

Discussion on the three types of ports: well-known, registered, and dynamic, with their respective number ranges.

Overview of popular protocols and their associated port numbers, using TCP or UDP.

Live demonstration on a Windows Server 2016 machine to identify protocols, ports, and services.

Use of Task Manager to view processes and services related to installed network protocols.

Command line tools 'netstat' and 'netstart' used to identify active network services and their ports.

Explanation of how 'netstat' shows the status of connections, IP addresses, port numbers, and associated process IDs.

Demonstration of how DHCP, DNS, and IIS services appear in the command line and Task Manager.

Illustration of how a web browser uses sockets to communicate with a web server on port 80.

Conclusion summarizing the importance of protocols, ports, and sockets in network communication.

Invitation for viewers to ask questions and engage with the content for further understanding.

Transcripts

[Music]

in this video we're going to talk about

protocols ports and sockets so we

already introduced what a protocol is

earlier in the course and if you

remember they're nothing more than rules

that dictate how we communicate back and

forth so in regards to a computer

network protocols are rules that govern

how machines exchange data and are able

to communicate with one another

effectively so in other words computers

use protocols to communicate back and

forth specifically networking protocols

and as you'll see in this video and in

this section there are quite a lot of

them that we're going to cover now when

you look on the operating system

themselves if you want to see what

protocols are running they're typically

called a process or a service and i went

ahead and i created a windows server

2016 virtual machine for this lecture

and i installed dns dhcp and the web

server on there just to show you how we

can identify these processes and servers

on a windows server 2016. now in regards

to protocols protocols are always going

to have a port number associated with

them and when we're talking about ports

we're not talking about the physical

ports like a usb port or an rj45 port

we're talking about a logical port so

when we're talking about protocols they

have a logical port that is bound to

them with a specific number so when

you're looking at processes and service

specifically a specific protocol

you're going to notice that each one has

a specific port number assigned to it in

addition to that we can take it one step

further when we combine an ip address

with a port number we call those a

socket and i'm going to demonstrate

those as well so what you see right here

is we see the ip address of 192.168.1.1

and we bound it to port 80. that's

called a socket and i'm going to

demonstrate that to you later in this

lecture when we get on to the windows

server 2016 machine so that's protocols

ports and sockets let's jump to the next

slide where we talk about protocols and

sockets and specifically why we need

them

so why do we need ports and sockets well

the answer is very simple it's because a

computer can have multiple different

protocols running at once and we need a

way to differentiate one from another so

for example right here we have a server

with an ip address of 192.168.1.100

and we set it up as an ftp server as

well as a web server and a dns server so

ftp is running on port 21. http for the

web server is running on port 80 and the

dns server is running on port 53. so

what we have to do to differentiate ftp

from http and dns is we have to assign

them that logical construct that port

number so when we're looking to access

an ftp server or an http server or dns

server we can say okay i need to go to

this ip address and specifically this

port number because i know ftp is

running on port 21 where i need to go to

port 80 because i know the web server is

running on port 80 for http so that's

the whole purpose because if we think

about this from the perspective of being

a server it's going to be multitasking

with a variety of network based

applications and we have to have a way

to differentiate one from another and

that's the whole point of having these

port numbers and having these sockets

which i'll demonstrate later in the

lecture so that's the reason why we need

a port number and a socket we can't

simply just say okay we're going to

start up ftp we're going to start up

http and we're going to start dns and

not bind them to any port number because

if we didn't then the system wouldn't be

able to differentiate one from another

and it's as simple as that so when we're

talking about port types and port

numbers there's three different types

and they have a certain amount of

different port numbers associated with

them so the first ones are the

well-known ports and those are going to

be port numbers 0 to 1023 these are

assigned to well-known protocols and

you're going to see some of those on the

preceding next two slides after that

there are what we call registered ports

that are also assigned to protocols but

they're not assigned to the most

well-known or the most used protocols

but they can be assigned to any sort of

protocol that an organization comes up

with they can request to have it

registered and it would be registered

within this range of 1024

up to 49

151

and then lastly we have what are called

dynamic ports which we'll talk about the

purpose of them later in this course but

they're designed for us to be able to

use them for our needs when we're

connecting to a server to request some

information or some data from them we

have to assign ourselves what we call a

dynamic port and you're going to notice

that these range from 49 152 up to 65

535

so that is the purpose of ports and

sockets so now let's go ahead and let's

take a look at some of the more popular

protocols and their associated port

numbers and whether they use tcp or udp

now what i've gone ahead and done in

this lecture is i put some of the more

popular ones in a table view but i'm not

going to go over them one by one in this

lecture because we have multiple

dedicated lectures further on in our

preceding tcp sections where we talk

about a lot of these protocols in depth

i just wanted to give you an idea of how

many there are in regards to the more

popular ones so you have an

understanding of what we're talking

about so let's take a look at my windows

server 2016 machine now and take a look

at protocols running as processes and

services and also do a demonstration of

a socket

all right so now you're looking at my

windows server 2016 virtual machine that

i set up for this video as a means to

give you a live demonstration of how we

can identify

protocols ports and services running on

a specific operating system now i want

you to understand before i get started

that you don't need to know how to do

all the stuff that i'm going to

demonstrate in this video there are some

commands that we're going to cover later

in the course so don't worry if you

don't understand what those are and how

they work we'll talk about them in much

detail later in the course the whole

purpose of this video is just to give

you the basics of how you can look at

this stuff within an operating system

and windows server 2016 is pretty

straightforward so i decided to use it

now what did i do with this well i went

ahead i installed it and i also added on

a dhcp server a dns server and a web

server so the web server for windows is

iis if you don't know what tcp or dns

does don't worry you don't need to know

that in this video because we're going

to cover that in much more detail later

in the course but i just want to show

you how we can actually identify them

within the operating system so we can

see that they're up and running here

within server manager but there's some

other ways that we can take a look at

them as well so what i can do is i can

go into task manager so i'm going to

right click down here go into task

manager

and within the windows operating system

we can notice and see that there is a

tab for processes and services so let's

take a look at this

so what you're going to notice is that

there is a process for iis running right

here and if i get rid of the highlighter

so i can scroll down further

you're going to notice that there's one

for dhcp up here as well

and let's see if we can identify one for

dns

so they're not always named in the most

straightforward manner but there's

always multiple different ways in which

we can find different services so what

you're going to notice down here is that

there is a service for the dhcp server

and there's also one there's actually

couple running for our web server down

here now

i can't easily identify one for dns so

what we can do is we can go over to our

services tab and we can see we can find

over here as well and if i scroll down

what we're going to notice is that we

can see one for dhcp we can actually see

a couple for dhcp

and we can see a couple for dns so what

you're going to notice is that there's

actually a service running for the

server and the client the client would

be the operating system as a client

meaning that it's using a dns server and

it's using a dhcp server for ip

addressing and to identify dns

information which will talk about what

dns and dhcp is later in the course

you're going to notice that there's a

process id the process id is not the

actual port number that's an id number

that the operating system assigns to

each service

so this tells us some basic information

but if we're not able to find everything

that we want to find we can actually go

to the command line and find some

additional information so let's go ahead

and minimize task manager and i'm going

to go ahead and open up a couple of

command lines what i've done is i've

already run a couple of commands on the

left i've run a net stand with some

switches in regards to netstat it's

going to tell us the status of specific

connections ones that were listing for

our different services in other words

our servers such as dhcp dns or web

server ones that we've actually

established with other systems and it's

going to show us the ip address with the

port number and hopefully you're

noticing that this is a socket something

that we talked about over here the

foreign address is who we're

communicating with and again these are

going to be sockets and the state of

whether it's listing or it's established

and the associated windows process id

over here on the right

we have another command called netstart

and this is essentially just going to

tell us all the windows services that

are starting and running

so let's start off by taking a look at

our netstar command that's just going to

show us the services that are running

and it's the same thing as looking over

here within our task manager looking at

the processes and the services but it's

a different view it's directly from

command line you're going to notice that

there is a little bit of a difference so

the first thing that i want to highlight

is that we can see that we have our dcb

client and server that we talked about

earlier as well as our dns client and

server

and of course the ones that we're really

concerned with are the servers so we can

see that both of those are running but

one of them that i had a hard time

finding earlier was the web server so if

i scroll all the way down to the bottom

what you're gonna find is here in the

command prompt it calls it world wide

web publishing services so rather than

calling it iis it calls us world wide

web publishing services so that gives us

some basic information it confirms that

it's up and running so what we can do

now is we can take a look at netstat so

what netstat does is it shows us the ip

address with the actual port and the

process id

so for our web server

that's going to always be running on

port 80 unless we change it so http runs

on port 80 and so what you're going to

notice with netstat is that we see it

running right here so it tells us that

our server is listing on this port

number and when you see all xeros

that's the server telling us that on any

ip address that you assigned to me if

you give me multiple different network

interface card interfaces then every

single one of them is going to be

listing in on port 80 so we're going to

see that right there

and then also we see

port 53 down here

and also port 53 down here

and let's see if we see it up here we

don't teed up here and we also see port

80 down here so port 53

is a port associated by default with dns

so dns is going to be listing in on the

ip address to see the actual ip address

assigned to the system

and 127.0.0.1

you're going to learn about that later

in the course that's the loopback

address that's just another address for

this system and down here this is going

to be

port 80 for ipv6 as well listening on

any ipv6 address that we assigned to the

system as well so we see dns we see

our web server but we do not see dhcp so

why is that well dhcp runs on port 67

and 68 the reason that you don't see it

is because i actually didn't finish

configuring it i have to assign it a

scope and i have to enable that scope

but i didn't do that because i had this

connected to my network at home and i

don't want to run into any conflict

issues with dhcp that's running on my

soho router what i want to do now is

actually take a look at the web browser

and show you a socket in action so what

i did is went ahead and typed in the ip

address of the system using http which

is a protocol that we're using for this

web server and let me go ahead and hit

enter again just to show you that this

is going to load and this is the default

web page for the web server now what

happens if i do

a socket

because i know that this is running on

port 80 if i do a socket with port 80

you're going to notice that it reloads

and it just gets rid of the socket

because it already knows the web browser

knows that we're running on port 80 but

what happens if i try port 443 which is

for http secure which means it's

encrypted if i try doing port 443 what

happens and i'll hit enter again on this

but you'll notice that it cannot connect

because i don't have the web server

configured for http secure i only have

it configured for port 80 for http so

that's going to go ahead and conclude

this video

if you have any questions regarding

protocols ports and sockets please let

me know and how i did all this stuff in

my windows server 2016 how i set up dhcp

and dns and iis you actually don't need

to know that but again i wanted to do a

live demonstration so thanks for

watching and i'll see you at the next

video take care

well i hope that you enjoyed today's

video and you learned a lot from it if

you did please give this video a thumbs

up and also consider subscribing to my

youtube channel now if you're interested

in taking this full course or just

learning more about it check out the

video description down below because

i've included a link where you can learn

more about the course and enroll into it

if you'd like so again thanks for

watching my video i appreciate it and i

look forward to seeing you guys at the

next video take care

[Music]

you