Networking Articles

Article / Updated 08-01-2022

Transmission control protocol/Internet protocol (TCP/IP), the protocol on which the Internet is built, is actually not a single protocol but rather an entire suite of related protocols. TCP is even older than Ethernet. It was first conceived in 1969 by the Department of Defense. Currently, the Internet Engineering Task Force, or IETF, manages the TCP/IP protocol suite. The TCP/IP suite is based on a four-layer model of networking that is similar to the seven-layer open systems interconnection (OSI) model. The following illustration shows how the TCP/IP model matches up with the OSI model and where some of the key TCP/IP protocols fit into the model. As you can see, the lowest layer of the model, the Network Interface layer, corresponds to the OSI model’s Physical and Data Link layers. TCP/IP can run over a wide variety of Network Interface layer protocols, including Ethernet, as well as other protocols, such as Token Ring and FDDI (an older standard for fiber-optic networks). The Application layer of the TCP/IP model corresponds to the upper three layers of the OSI model — that is, the Session, Presentation, and Application layers. Many protocols can be used at this level. A few of the most popular are HTTP, FTP, Telnet, SMTP, DNS, and SNMP. IP IP is a network layer protocol that is responsible for delivering packets to network devices. The IP protocol uses logical IP addresses to refer to individual devices rather than physical (MAC) addresses. A protocol called ARP (for address resolution protocol) handles the task of converting IP addresses to MAC addresses. Because IP addresses consist of a network part and a host part, IP is a routable protocol. As a result, IP can forward a packet to another network if the host is not on the current network. (The ability to route packets across networks is where IP gets its name. An Internet is a series of two or more connected TCP/IP networks that can be reached by routing.) TCP TCP is a connection-oriented transport layer protocol. TCP lets a device reliably send a packet to another device on the same network or on a different network. TCP ensures that each packet is delivered if at all possible. It does so by establishing a connection with the receiving device and then sending the packets. If a packet doesn’t arrive, TCP resends the packet. The connection is closed only after the packet has been successfully delivered or an unrecoverable error condition has occurred. One key aspect of TCP is that it’s always used for one-to-one communications. In other words, TCP allows a single network device to exchange data with another single network device. TCP isn’t used to broadcast messages to multiple network recipients. Instead, the user datagram protocol (UDP) is used for that purpose. Many well-known application layer protocols rely on TCP. For example, when a web browser requests a page, the browser uses HTTP to send a request via TCP to the web server. When the web server receives the request, it uses HTTP to fulfill the request, again via TCP. Other Application layer protocols that use TCP include Telnet (for terminal emulation), FTP (for file exchange), and SMTP (for e-mail). UDP The user datagram protocol is a connectionless transport layer protocol that is used when the overhead of a connection isn't required. After UDP has placed a packet on the network (via the IP protocol), it forgets about it. UDP doesn't guarantee that the packet actually arrives at its destination. Most applications that use UDP simply wait for any replies expected as a result of packets sent via UDP. If a reply doesn't arrive within a certain period of time, the application either sends the packet again or gives up. Probably the best-known application layer protocol that uses UDP is the domain name system (DNS). When an application needs to access a domain name such as www.dummies.com, DNS sends a UDP packet to a DNS server to look up the domain. When the server finds the domain, it returns the domain's IP address in another UDP packet.

Cheat Sheet / Updated 04-20-2022

Amazon Web Services (AWS) started out small, but has become a vast collection of cloud services that businesses can use to support any activity without having to invest in an IT infrastructure.

Cheat Sheet / Updated 03-01-2022

To create and configure a Cisco network, you need to know about routers and switches to develop and manage secure Cisco systems. Become acquainted with Cisco network devices and code listings; and find out how to manage static routing and view routing information.

Cheat Sheet / Updated 02-28-2022

As a network administrator, you know that TCP/IP is the glue that holds the Internet and the Web together. As well as being familiar with security terms and general definitions, you need to pay attention to RFCs (Requests for Comment) published by the Internet Engineering Task Force. You can comment on, learn from, and submit RFCs yourself.

Cheat Sheet / Updated 02-23-2022

Digital transformation is the mantra of many organizations. There is no debate about it: Cloud computing has changed the way businesses operate. Small and mid-sized organizations may be all in on the cloud, while large enterprises are a hybrid and multicloud strategy. The cloud is helping startups challenge industry stalwarts, while at the same time, traditional companies are changing. The first phase of cloud adoption was mostly about cutting costs and changing technology spend from a capital expense to an operating expense. For many years, cloud vendors were focused on reducing costs for commodity compute and storage. While reducing costs is still a major driver of cloud adoption, companies are now leveraging cloud services to transform their businesses. The focus of cloud computing has shifted from reducing costs to gaining business agility, providing developers with the tools they demand and ultimately providing excellent customer care. It’s safe to assume that your organization uses some kind of cloud computing, whether it’s a CRM (customer relationship manager) or HR (human recourses) Software as a Service offerings or Cloud native container-based software development services.

Cheat Sheet / Updated 02-03-2022

PowerShell 5.1 is the version of Windows PowerShell that ships with Windows Server 2022, Windows Server 2019, and Windows Server 2016. It’s available for installation on Windows Server 2008 R2 with Service Pack1, Windows Server 2012, and Windows Server 2012 R2. The last three operating systems must have Windows Management Framework 5.1 installed to support PowerShell 5.1. You can upgrade to PowerShell 7.2 fairly easily (the more recent version from Microsoft), though the examples on this Cheat Sheet were only tested in PowerShell 5.1.

Article / Updated 12-27-2021

When you first create a file share on your network, all users are granted read-only access to the share. If you want to allow users to modify files in the share or allow them to create new files, you need to add permissions. Here’s how to do this using Windows Explorer: Open Windows Explorer by pressing the Windows key and clicking Computer; then browse to the folder whose permissions you want to manage. Right-click the folder you want to manage and then choose Properties from the contextual menu. The Properties dialog box for the folder appears. Click the Sharing tab; then click Advanced Sharing. The Advanced Sharing dialog box appears. Click Permissions. The dialog box shown appears. This dialog box lists all the users and groups to whom you’ve granted permission for the folder. Initially, read permissions are granted to a group called Everyone, which means that anyone can view files in the share but no one can create, modify, or delete files in the share. When you select a user or group from the list, the check boxes at the bottom of the list change to indicate which specific permissions you’ve assigned to each user or group. Click the Add button. The dialog box shown appears. Enter the name of the user or group to whom you want to grant permission and then click OK. If you’re not sure of the name, click the Advanced button. This action brings up a dialog box from which you can search for existing users. When you click OK, you return to the Share Permissions tab, with the new user or group added. Select the appropriate Allow and Deny check boxes to specify which permissions to allow for the user or group. Repeat Steps 5–7 for any other permissions that you want to add. When you’re done, click OK. Here are a few other thoughts to ponder concerning adding permissions: If you want to grant full access to everyone for this folder, don’t bother adding another permission. Instead, select the Everyone group and then select the Allow check box for each permission type. You can remove a permission by selecting the permission and then clicking the Remove button. If you’d rather not fuss with the Share and Storage Management console, you can set the permissions from My Computer. Right-click the shared folder, choose Sharing and Security from the contextual menu, and then click Permissions. Then you can follow the preceding procedure, picking up at Step 5. The permissions assigned in this procedure apply only to the share itself. The underlying folder can also have permissions assigned to it. If that’s the case, whichever of the restrictions is most restrictive always applies. If the share permissions grant a user Full Control permission but the folder permission grants the user only Read permission, for example, the user has only Read permission for the folder.

Article / Updated 12-27-2021

Although an occasional sacrifice to the Office gods may make your networking life a bit easier, a template isn’t a place of worship. Rather, a template is a special type of document file that holds formatting information, boilerplate text, and other customized settings that you can use as the basis for new documents. Three Office programs — Word, Excel, and PowerPoint — enable you to specify a template whenever you create a new document. When you create a new document in Word, Excel, or PowerPoint by choosing File → New, you see a dialog box that lets you choose a template for the new document. Office comes with a set of templates for the most common types of documents. These templates are grouped under the various tabs that appear across the top of the New dialog box. In addition to the templates that come with Office, you can create your own templates in Word, Excel, and PowerPoint. Creating your own templates is especially useful if you want to establish a consistent look for documents prepared by your network users. For example, you can create a Letter template that includes your company’s letterhead or a Proposal template that includes a company logo. Office enables you to store templates in two locations. Where you put them depends on what you want to do with them: The User Templates folder on each user’s local disk drive: If a particular user needs a specialized template, put it here. The Workgroup Templates folder on a shared network drive: If you have templates that you want to make available to all network users on the network server, put them here. This arrangement still allows each user to create templates that aren’t available to other network users. When you use both a User Templates folder and a Workgroup Templates folder, Office combines the templates from both folders and lists them in alphabetical order in the New dialog box. For example, the User Templates folder may contain templates named Blank Document and web Page, and the Workgroup Templates folder may contain a template named Company Letterhead. In this case, three templates appear in the New dialog box, in this order: Blank Document, Company Letterhead, and web Page. To set the location of the User Templates and Workgroup Templates folders, follow these steps in Microsoft Word: In Word, create a new document or open an existing document. It doesn't matter which document you use. This step is required simply because word doesn't let you access the template folder locations unless a document is open. Choose File, and then Options. The Word Options dialog box opens. Click the Advanced tab. The Advanced options appear. Scroll down to the General section and then click the File Locations button. The File Locations dialog box appears. Double-click the Workgroup Templates item. This step opens a dialog box that lets you browse to the location of your template files. Browse to the template files and then click OK. You return to the File Locations dialog box. Click OK to dismiss the File Locations dialog box. You return to the Word Options dialog box. Click OK again. The Word Options dialog box is dismissed. Although the User Templates and Workgroup Templates settings affect Word, Excel, and PowerPoint, you can change these settings only from Word. The Options dialog boxes in Excel and PowerPoint don’t show the User Templates or Workgroup Templates options. When you install Office, the standard templates that come with Office are copied into a folder on the computer’s local disk drive, and the User Templates option is set to this folder. The Workgroup Templates option is left blank. You can set the Workgroup Templates folder to a shared network folder by clicking Network Templates, clicking the Modify button, and specifying a shared network folder that contains your workgroup templates.

Step by Step / Updated 12-27-2021

User accounts are among the basic tools for managing a Windows server. As a network administrator, you’ll spend a large percentage of your time dealing with user accounts To create a new domain user account in Active Directory, follow these steps:

Article / Updated 12-27-2021

One of the most useful tools available to system administrators is a program called Remote Desktop Connection. Remote Desktop Connection lets you connect to a server computer from your own computer's desktop and use it as though you were actually sitting at the server. The program enables you to manage your servers from the comfort of your own office, without having to walk down to the server room. Remote Desktop Connection is especially important if you're using virtual servers. Because virtual servers have no real hardware, including keyboards, mice, or monitors, Remote Desktop Connection is the primary way you interact with them. Before you can use Remote Desktop Connection to access a server, you must enable remote access on the server. You can do that from the System Properties dialog box. Here are the steps: Open the Control Panel. Double-click System. Click the Remote Settings link. Click the Remote Tab. Select the Allow Remote Connections to This Computer radio button. Click OK. All versions of Windows come with a program called the Remote Desktop Client, which you can use to connect to a server remotely. Here are the steps for Windows 7: Click the Start button, type the word Remote, and then click the Remote Desktop Connection icon. Enter the name of the server you want to connect to. Click the Connect button. Log on and use the server.