Local Area Networking

It’s important to understand IP addressing schemes and to see how TCP and IP work together to make the internet work.

The first step towards understanding IP addressing flexibility is to understand network IDs and how they interact with a subnet mask to get packets delivered to the right system.

From loopback to private IP addresses, a good tech understands special reserved addresses as well as when and how to use them.

Network Address Translation, or NAT, provides some amazing benefits but also has some serious limitations.

To avoid the nightmare of manually entering IP addresses, smart techs use the Dynamic Host Control Protocol (DHCP) to automatically provide IP addressing to individual hosts.

IPv6 adds several benefits over IPv4 and good techs know how to use it in our systems.

It’s critical to understand how port numbers do their job and to memorize many special port numbers.

User Datagram protocol (UDP) and Internet Control Message Protocol (ICMP) both serve important purposes and features that techs need to understand.

A good tech knows how to use common utilities to observe connections and diagnose issues.

To make our lives easier, most TCP/IP networks (and certainly the Internet) use the Domain Naming System (DNS) to apply human-friendly names to systems.

There are a few simple tools and procedures to diagnose and repair DNS problems.

Microsoft introduced a series of naming protocols, some of which predate the internet.

Workgroups are simple and provide no security, but they’re a part of every small Windows network.

More advanced Windows networks use domains instead of workgroups, providing powerful services for larger networks.

Both Mac and Linux systems know how to use Windows naming functions; the trick is to understand how they do it and to configure them to work with an existing Windows network.

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

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?

All routers share some basic configuration steps every tech must know.

Setting up a hardware firewall is an obvious first step to making sure your network is well-protected.

Unlike the firewall on your router, the Windows software firewall only protects a single system, and it’s important for techs to understand how to use it.

Port forwarding allows opening specific ports on your NAT-enabled router to provide access to servers behind it.

Protocols such as Quality of Service, Universal Plug and Play and Simple Network Management Protocol give extra features to enhance the capabilities of your router.

VLANs provide superb control of your LAN but have their own quirks that a good tech understands.

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