The technical requirements are as follows:

• Windows machine
• Ping utility through Windows Command Prompt

The term ports or network ports usually means the physical interfaces or ports on a device, such as a router, switch, server, or even a personal computer. A physical port also known as an interface is the connector on a local system such as computer where an Ethernet cable to attach which connects the device to the rest of the network. However, even though these are the physical ports, there are also logical ports within an operating systems or a device. You may ask yourself, how does a physical port exist within a computer, server, or network appliance such as a router or switch? Here, we are going to further break down the concepts of these logical ports or what are known as network ports.

To get started, we will use a simple analogy to help you understand the fundamentals of logical ports on a system. Let's imagine you own an organization; at the organization...

A network protocol defines the rules and procedures in which data communication occurs among devices over a network. Without predefined rules or procedures, the messages traversing a network would be without any particular formatting and may not be meaningful to the recipient device. To further discuss the importance of having protocols on a network/system, we will use the following analogy to provide you with a real-world situation compared to network protocols.

Let's imagine you work for an organization, ACME Corporation, and within the company there are many policies and procedures that govern the handling of day-to-day transactions and activities within the organization. One of the most important procedures is the emergency evacuation plan. If there's an emergency within the organization, the procedure documents the rules and guidelines each employee...

In this section, we are going deeper into discussing various types of protocols and their characteristics. We are going to cover the functionality of Internet Control Message Protocol (ICMP), TCP, UDP, and IP.

On a network, whether on a Local Area Network (LAN) or a Wide Area Network (WAN), host devices will be communicating to exchange data and information among one another and sometimes an error can occur. Let's imagine you are sending a packet to a server on the internet, and, while your computer is initializing the connection between itself and the remote server, it provides an error stating, it is unable to connect. As an upcoming networking professional, you may wonder why both devices are unable...

Here, we are going to discuss some of the well-known protocols at the Application Layer.

FTP defined by RFC 959 is used to transfer files between systems either on a LAN or a remote network. This is beneficial to users who would like to simply upload, download, or even remove files from a remote system. FTP provides user authentication: a username and password combination as an extra layer of security.

Unlike some protocols, FTP uses two ports, port 20 is used for Data (data transfer) and port 21 is for Control (parsing of commands):

A network topology is simply the orientation or the layout of objects that are interconnected for the purpose of communication or sharing resources. To put it simply, it's the network diagram displaying where devices are located, the type of media used to physically connect the components, the interfaces or the physical ports used, and the IP addresses of each device.

In the following section, we'll dive a bit deeper into understanding the characteristics and features of the different types of topologies.

The star topology is simple and is used in most modern-day networks. The name star was derived from the from the actual layer of the devices; all of the clients or host devices are connected...

In this section, we will discuss the different type of networks:

• Local Area Network (LAN): LAN is a small network within a home, an office or even a building.
• Wide Area Network (WAN): The purpose of a WAN is simply to extend a LAN over a large geographic distance. Imagine you own a company—at the moment, it's only a single office location; however, as time passes, your business expands to another branch office in another city or country. Since the first branch has all of your main servers and network resources, it becomes the head office. The challenge is to allow the other branch office(s) to share the existing network resources from the head office to the other branch location. The solution is to implement a WAN connection between the offices:

• Wireless Local Area Network (WLAN): A WLAN is where either an Access Point (AP) or a wireless router...

At times, we usually hear the term Ethernet when discussing networking, whether within a classroom or with network professionals, but what exactly is Ethernet? Here, we'll take a look at the fundamental characteristics and its functionality on a network.

In the previous chapter, we spoke about the OSI reference model and the TCP/IP stack. We've observed that layer 2 (Data Link Layer) is where the Protocol Data Units (PDUs) are either entering or exiting a system and layer 1 (Physical Layer) is the actual media used for transporting the bits. At these two layers, both the Physical and the Data Layers, we can find Ethernet:

Ethernet, defined by IEEE 802.3, is a standard that defines how network communications occur, such as the encoding and decoding of a message, the synchronization of the flow of messages, the format for messages...

In this chapter, we've taken a look at port numbers and their importance on a system. Without port numbers per services, a computer will have a challenge processing any messages it has received from a sender. For every port number, there's a service or network protocol that is mapped to it. Each network protocol handles the formatting and encoding of data in its own way and uses a unique port number for communicating with another device. So far, this chapter provided a better understanding in understanding and identifying network protocols and port numbers and understanding network design.

In the next chapter, we'll be covering Ethernet a bit more in-depth while providing the functions of its sub-layers and the fields within an Ethernet frame.

1. Which protocol exist at the Internet Layer of the TCP/IP stack?
   1. TCP
   2. IP
   3. UDP
   4. ARP
2. Which protocol sends a message without first establishing a session?
   1. DHCP
   2. TCP
   3. HTTP
   4. UDP

3. When a user opens their web browser, the browser is unable to reach www.google.com; however, you are getting success responses after you ping the IP address 8.8.8.8. Which protocol may be affected?
   1. HTTP
   2. IP
   3. SMTP
   4. DNS
4. You're a network administrator at a local company, and the IT department has recently installed a new email server within the organization. Your task is to ensure all employees computers are configured to send email successfully. Which protocol would be used for sending email?
   1. POP
   2. SMTP
   3. IMAP
   4. HTTP
5. A company has a single location and, after a year, it is able to open another branch office far way. However, the manager of the company wants to extend their local network resources...

Read the following articles for more information:

• Check out the CompTIA Network+ Cert (N10-007): Full Course and Practice Exam [Video] at https://www.packtpub.com/networking-and-servers/comptia-network-cert-n10-007-full-course-and-practice-exam-video.
• To get more information on all the existing network protocols with their port assignment, you can visit the Internet Assigned Numbers Authority's Protocol Registries at https://www.iana.org/protocols.