Networking

Syllabus

Network troubleshooting

Video - 00:05:00

Networks sometimes fail. A good network tech knows how read symptoms and diagnose a network quickly to enable users to get back to work.

Virtual LANs (VLANs)

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Virtual LANs (VLANs) are common features built into almost all switches. VLANs provide superb control of your LAN but have their own quirks that a good tech understands.

Advanced router configuration

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Even the most basic router has setting beyond the basic setup. Protocols such as Quality of Service (QoS), Universal Plug and Play (UPnP), and Simple Network Management Protocol (SNMP) give extra features to enhance the capabilities of your router.

Port forwarding

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NAT is a handy tool but comes with a huge drawback: no servers behind the firewall are accessible to the outside world. Port forwarding allows opening specific ports on your NAT-enabled router to provide access to servers behind it.

Windows firewall

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Like all operating systems, Windows comes with a built-in software firewall. Unlike the firewall on your router, this firewall only protects a single system. It’s important for techs – and the users they support – to understand how to use the Windows firewall.

Firewall configuration

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Setting up a hardware firewall is an obvious first step to making sure your network is protected. Even the most basic router has several different types of firewall settings – without proper configuration you’ll either leave your network wide open, or so restricted no one can get work done.

Basic router configuration

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All routers share some basic configuration steps every tech must know. From router passwords to LAN IDs, this is the place to learn about these settings.

Routers

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The CompTIA A+ exams challenge test takers to perform many configurations of a typical home router. But what does a router do for a SOHO network?

The net command

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The Windows net command has so many features that it deserves its own episode. We use the net command for everything from querying the network to accessing shares.

Windows sharing with macOS and Linux

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Both macOS and Linux systems know how to use Windows naming functions to connect using workgroups and domains and share resources using Samba. The trick is to understand how they do it and to configure them to work with an existing Windows network.

Working with active directory

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More advanced Windows networks use active directory domains instead of workgroups. These domains, especially Microsoft’s Active Directory-enabled domains, provide powerful services for larger networks.

Working with workgroups

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Microsoft developed the concept of workgroups for small networks to work with their naming system. Workgroups are simple and provide no security, but they’re a part of every small Windows network.

Windows naming

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Microsoft introduced a series of naming protocols, some of which predate the Internet. Interestingly, these protocols (or at least their modern versions) are still alive and well not only on Windows systems, but on Linux and macOS systems as well.

Working with DNS

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When a user complains the Internet is down, what’s often happening is that DNS isn’t working. There are a few simple tools and procedures to diagnose and repair DNS problems.

Understanding DNS

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Individual hosts use IP addresses, but humans are terrible at memorizing long strings of numbers. To make our lives easier, most TCP/IP networks (and certainly the Internet) use the Domain Name System (DNS) to apply more human-friendly names to systems. DNS can also make use of various spam management protocols such as DKIM, SPF, and DMARC.

Working with connections

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When two computers begin the process of sharing data, they create what we call a connection (or session). A good tech knows how to use common utilities to observe these connections and diagnose issues.

TCP, UDP and ICMP

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TCP is the most popular IP protocol, but it isn’t the only one. User Datagram Protocol (UDP) and Internet Control Message Protocol (ICMP) both serve important purposes and features that techs need to understand.

Port numbers

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An IP address directs a packet to the right computer, but it’s the port number that makes a connection between two applications on separate systems. It’s critical to understand how port numbers do their job and to memorize many special port numbers.

IPv6

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The traditional IP addressing scheme (called IPv4) is quickly being replaced with the much more advanced IPv6 scheme. IPv6 adds several benefits over IPv4 and good techs know how to use it in our systems.

Dynamic IP addressing

Video - 00:10:00

Manually entering IP addresses into all our devices is an administrative nightmare. To avoid this mess, smart techs use the Dynamic Host Configuration Protocol (DHCP) to automatically provide IP addressing to individual hosts.

Network address translation (NAT)

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You’d be hard pressed to find a home or small office router that isn’t using Network Address Translation (NAT). NAT provides some amazing benefits but also has some serious limitations.

Special IP addresses

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The designers of IP addressing reserved many IP addresses for special uses. From loopback to private IP addresses, a good tech understands these special addresses as well as when and how to use them.

Network IDs and subnet masks

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IP addressing was designed from the ground up for flexibility in supporting LANs and WANs of any size. The first step towards understanding this flexibility is to understand Network IDs and how they interact with a subnet mask to get packets delivered to the right system.

Introduction to TCP/IP

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The Transmission Control Protocol/Internet Protocol (TCP/IP) is the cornerstone of Internet addressing and routing. It’s important to understand IP addressing schemes and to see how TCP and IP work together to make the Internet work.

Network card troubleshooting

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Network hardware failures are often challenging to diagnose and repair. Good techs know a few simple tools and procedures to get networks back up and running quickly.

Structured cabling

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Structured cabling is the process of installing and organizing cable systems to ensure long term, reliable connections. While CompTIA doesn’t want you to be a cable installer, a good tech understands structured cabling and can work with installers.

Crimping cables

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CompTIA doesn’t expect you to prove you can crimp your own cables, but it does expect you to understand the crimping process. Additionally, you must know EIA standards for crimping cables.

Cables and connectors

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Networking uses many different types of cables such as coaxial, twisted pair, and even fiber-optic. These different cables use special connectors and a good tech should recognize the different cables and their connectors.

WANs and routers

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When a router connects two or more LANs, it creates a Wide Area Network. To understand WANs, it’s critical to understand routers and how they use logical addressing.

Hexadecimal

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Hexadecimal numbering uses a base-16 system that’s very convenient for IT techs. It’s important to look at a hex value and understand the equivalent binary value.

Hubs vs switches

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The central box that connects devices on our LANs has gone through many advancements over the years. Whether hubs or switches, a good tech understands the function and features of these boxes in our LANs.

Introduction to networking

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You’ll never understand the power of the Internet without first starting at the most basic form of networking: the Local Area Network (LAN). LANs use a central piece of hardware to interconnect individual devices, transferring data from one system to another in discrete frames.