Certified - CompTIA Tech+ Prepcast

Networking is the practice of connecting devices so they can communicate and share data. It enables file transfers, internet access, and resource sharing between computers, servers, and other systems. The CompTIA Tech Plus certification includes key networking concepts such as internet protocol addressing, media access control addressing, and communication protocols. Understanding these fundamentals supports roles in support, security, and system administration. This episode begins with addressing, ports, and the basic flow of data across networks.
Internet protocol addressing is the system used to uniquely identify devices on a network. Version four addresses use four octets in decimal form, such as one hundred ninety two dot one hundred sixty eight dot one dot one. Version six addresses use one hundred twenty eight bits in hexadecimal notation, allowing far more combinations. Addresses can be manually assigned, called static, or assigned automatically by a dynamic host configuration protocol server. Every device must have a unique address to communicate without conflicts.
Private internet protocol addresses are used within local networks and include ranges such as one hundred ninety two dot one hundred sixty eight dot x dot x and ten dot x dot x dot x. Public internet protocol addresses are routable on the internet and are assigned by internet service providers. Routers convert private addresses to public ones using network address translation. Knowing whether an address is private or public is important for setting firewall rules and controlling access.
Subnetting is the process of dividing a network into smaller segments to improve management, security, and traffic flow. A subnet mask, such as two hundred fifty five dot two hundred fifty five dot two hundred fifty five dot zero, determines which part of an address identifies the network and which part identifies the host. Classless inter-domain routing notation, such as slash twenty four, is used to indicate subnet size. Subnetting skills are useful for routing and network segmentation tasks.
Media access control addresses are unique identifiers assigned to physical network interfaces by their manufacturers. They are composed of twelve hexadecimal digits, often written as pairs separated by colons, such as zero zero colon one A colon two B colon three C colon four D colon five E. These addresses are permanently assigned and are used for communication within local networks and for identifying devices on switch ports.
Internet protocol and media access control addresses serve different purposes and operate at different layers. Internet protocol works at the network layer, while media access control functions at the data link layer. An internet protocol address can change depending on location or configuration, but a media access control address is fixed to its device. Devices use media access control addresses for local delivery after resolving an internet protocol address to a hardware address using the address resolution protocol table.
Ports are used to identify specific services running on a device. They are numbered from zero to sixty five thousand five hundred thirty five, with well-known ports ranging from zero to one thousand twenty three. For example, hypertext transfer protocol uses port eighty, hypertext transfer protocol secure uses port four hundred forty three, file transfer protocol uses port twenty one, and secure shell uses port twenty two. Knowing these port numbers is important for recognizing and securing network traffic.
Transmission control protocol and user datagram protocol are two major transport layer protocols. Transmission control protocol is connection oriented and ensures reliable delivery of data. User datagram protocol is faster but connectionless and less reliable. Transmission control protocol is used for applications such as web browsing, email, and file transfer, while user datagram protocol is used for streaming, voice over internet protocol, and online gaming where speed is more critical than guaranteed delivery.
Ports play a central role in how network services operate. Servers listen on specific ports for incoming requests. Firewalls can allow or block ports to control traffic. Port forwarding can redirect traffic from one port to a different service or device. Misconfigured ports can lead to service failures or create security vulnerabilities, making proper configuration an important administrative task.
The domain name system is a service that converts human-friendly names into internet protocol addresses. For example, typing w w w dot example dot com into a browser resolves to a numerical address such as ninety three dot one hundred eighty four dot two hundred sixteen dot thirty four. Domain name system queries use port fifty three with user datagram protocol and can be cached for faster lookups. Problems with this service can make websites or applications inaccessible even when the network connection is otherwise functional.
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Dynamic host configuration protocol is a network service that automatically assigns internet protocol addresses to devices when they connect. This simplifies network administration and removes the need for manual configuration on each device. It operates over user datagram protocol using ports sixty seven and sixty eight. In addition to the address itself, the service also provides settings for lease time, default gateway, domain name system servers, and subnet mask.
Static addressing means that an internet protocol address is manually assigned to a device and does not change. This is used for devices such as servers, printers, and network equipment that require consistent access or port forwarding. Dynamic addressing changes over time and is common for client devices in both home and office networks. Understanding when to use static versus dynamic assignment is important for planning and troubleshooting.
Network address translation allows multiple private internet protocol addresses to share a single public address for internet access. It translates private addresses to the public address and tracks connections so that replies are sent to the correct device. This is commonly implemented on home routers and firewalls. While it improves security and conserves public addresses, it can introduce complications for applications such as voice over internet protocol or certain online games.
Common network services use specific protocols and ports. Web services typically use hypertext transfer protocol or hypertext transfer protocol secure. File transfers may use file transfer protocol or server message block. Email relies on simple mail transfer protocol, post office protocol version three, or internet message access protocol. Remote management tools include secure shell, telnet, and remote desktop protocol. Each service has a default port and protocol that must be allowed on the network for proper operation.
Local area networks connect devices within a limited physical space such as a home, office, or lab. They typically use Ethernet cabling, switches, and wireless access points. These networks offer high speed and low latency for internal communication and resource sharing. Local area networks form the foundation of most private business and residential networks.
Wide area networks connect devices or multiple networks across large geographic areas. The internet is the largest public wide area network. These connections can use leased lines, virtual private networks, or dedicated fiber links to connect remote sites. Understanding wide area network concepts is important for diagnosing issues that span multiple locations.
The client server model is a network design where client devices request services from centralized servers. This is common for web applications, email systems, and databases. Centralized management makes updates and maintenance easier. Clients must be properly configured to find and authenticate with the server in order to access services.
In a peer to peer model, devices share resources directly without a central server. This can be used in small networks or for file sharing applications. Peer to peer is generally easier to set up but can be more difficult to secure and manage at scale. The Tech Plus exam may include questions comparing client server and peer to peer models in different scenarios.
Several tools are essential for network troubleshooting. Ping checks connectivity and measures latency to a remote device. Traceroute shows the path that packets take through the network and where delays occur. The I P config or ifconfig command displays local network configuration details including address, subnet, and gateway. The N S lookup or dig command can verify domain name system resolution.
For the exam, you may encounter scenarios that require identifying the correct protocol, port, or type of address for a given problem. This can include diagnosing an address conflict, determining the cause of a domain name system failure, or recognizing an incorrect subnet mask. Understanding the flow of communication from source to destination is essential for accurate troubleshooting and high scoring performance.
Key glossary terms for review include internet protocol address, media access control address, subnet, network address translation, dynamic host configuration protocol, domain name system, transmission control protocol, user datagram protocol, port, local area network, and wide area network. Grouping these terms by their place in the network model can deepen understanding. Flashcards and mapping exercises that connect these terms to real network diagrams will reinforce learning.
In real world environments, I T support professionals troubleshoot address conflicts, resolve domain name system issues, and restore services that have been interrupted by port or protocol problems. System administrators configure port forwarding, dynamic host configuration protocol scopes, and static address reservations. Help desk staff often walk users through diagnosing internet connectivity issues and configuring email. These networking basics are core skills across all areas of information technology.
This concludes our coverage of networking fundamentals for addressing, ports, and communication. In the next episode, we will examine network services such as file transfer, email, and secure browsing. You will learn how service ports and protocols enable devices to communicate both within a local area network and across the internet.