Subnetting Cheat Sheet

Subnetting Cheat Sheet For Quick Reference

Subnetting is a method of segmenting hosts within a network and providing additional structure hosts within a network and providing additional structure. Without subnets, an organization operates as a flat network. These flat topologies result in short routing tables, but as the network grows, the use of bandwidth becomes inefficient.

Classes	1st Octet Range	Network Bits	Possible Networks	Host Bits	No. of Hosts per Network
A	1-126	8	126	24	16,777,216
B	128-191	16	16,384	16	65,536
C	192-223	24	2,097,152	8	256

Note: The total number of available hosts on a network can be derived by using the formula 2^n-2, where n is the number of host bits. The -2 accounts for an octet with all 0s, which is reserved for network identification, and all 1s, which is reserved for sending a broadcast message to all hosts.

Cisco Network Magic Pro 5.5

Features

• Easy to use - No IT Expertise Needed
• Perform tasks from centralized location
• An enhanced interface plus new in-product wizards streamline networking tasks, taking the guesswork and effort out of getting connected, monitoring activity and repairing your network.
• Connect to the network
• Add a Device
• Easily connects all of the devices you use in your daily life; computers, printers, cameras and game consoles to your wireless or broadband network.
• Go Wireless
• "Go Wireless" helps you connect your computers and devices to a secure network.
• NAS Support
• Connect Network Attached Storage (NAS) devices to your network, allowing you to easily back up your data.
• Share Folders and Printers
• Share Printers and Files
• Eliminate the need to email yourself to get access to files or print documents from different computers.
• Protect
• New Security Enhancements
• Add protection to your network with wireless protection (encryption support for WPA), enabling you to lock out intruders. Plus, easily change your router password in Network Magic instead of having to log-in to your router admin utility.
• Monitor and Control
• New Parental Monitoring
• Gives parents the ability to monitor their kids' online activity. Restrict Internet access plus take real-time desktop screenshots to track websites visited and programs used, providing peace of mind and a safer online experience.
• Network Reports
• Viewed detailed activity reports for each computer on your networkl informing you of web sites visited, software application used, and devices added or removed.
• Manage and Troubleshoot
  
  • Internet Speed Test
    
    • Test your Internet speed so you can be aware of service or performance issues.
  • Health and Security Alerts
    
    • Proactively monitors and informs you of your network's activity and health, giving you advice on how to resolve issues and improve your online experience.
  • Internet Connection Repair
    
    • Quickly troubleshoot, pinpoint, and repair Internet connection problems.
• Cross-platform Support
  
  • Create a seamless network across Windows 7, Vista, XP and Mac so you can easily share printers and files across alll of your computers.
  • Network Magic for MAC Add-on
    
    • Integrate Macs and PCs into one network.

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The Internet Infrastructure and How It Connects

How The Internet Connects

The internet is connected when a user logs into their pc and browse a website by typing in the url. The URL is known as a Domain Name Server; which maps domain names to their IP address. In order for you to even connect to the internet, you must have a Local ISP or Access Providers. Your Local ISP is connected to a regional access router which pools other local ISPs. The regional access router are connected to back haul providers. Back haul providers is capable of handling the massive amounts of Internet traffic that continues to grow.

Definitions You Should Know

	Access Providers The web is really made of many networks connected in a hierarchy. Local Internet service Providers (ISPs) typically give residential and small business access to the Internet. Regional providers typically connect serveral local ISPs to each other and to back haul providers that connect with other regional poroviders.
	Domain Name Server (DNS) This server maps domain names to their IP addresses. One of the main reasons that the Internet has taken off in use and popularity is because www.ccnacentral.info is much easier to remember than. 34.123.13.3.
	Web Servers All web pages are stored on computers called web servers. Thousands of these servers can be dedicated servers for companies, hosting servers that house many personal pages, or even single computers housing individual pages.
	Back Haul Providers A few back haul providers comprise the high-speed backbone of the Internet. Only a handful of these providers are capable of handling the massive amounts of Internet traffic that continues to grow. Many parts of the back haul providers overlap with each other, which improves both the speed and reliability of the network.

Helpful Sites

• Local Internet Service Provider: AT&T
• Domain Name Service Provider: DynDNS.com

How to install DD-WRT onto your Linksys Cisco Home Router

Installation

Installing DD-WRT on your Linksys Cisco Router is almost as simple as installing a program onto your computer. The bad part is; if done incorrectly, you can brick your router. Installing programs on a router is known as a firmware, is done through flashing. This article will help you install DD-WRT onto your Linksys Cisco Home Router.

Identifying your Linksys Cisco Router

Visit this website to accurately identify which model your Linksys Cisco router is. Start with the brand name Cisco Linksys and go down the list.

Flashing Instructions

1. First and foremost, you will need to download the DD-WRT file that you've identified is your model and save it to a location that you will be able to locate later to flash your router.
2. Log into the Linksys stock firmware and choose to reset to defaults.
3. Do a hard reset on your router (hold the reset button down for 30 seconds.) 
4. After your router has been set to default settings and you've done a hard reset, log into your Linksys firmware by typing 192.168.1.1 into your browser.
5. Click on the "Administration" tab
6. Click on the "Firmware Upgrade" sub-tab.
7. Click the "Browse" button and select the DD-WRT .bin file you downloaded and placed in a location you remembered earlier.
8. Click the "Upgrade" button.
9. The router will take a few minutes to upload the file and flash the firmware. You should see the power light flash multiple times, dont panic. This is normal.
10. Once the firmware has been uploaded, a new page will open confirming that the upload was successful. Now wait about 3-5 minutes before clicking "Continue".
11. Lastly, do another hard reset on your router.
12. To check that you've successfully and correctly installed DD-WRT, type in 192.168.1.1 in your web browser to be able to see the DD-WRT web interface.

Reverting Back to Stock

Should you want to revert back to your router's stock firmware, you should be able to download the stock firmwaire from the Linksys's site and flash using the webgui.

Helpful Sites

• DD-WRT Installation site
• How to install custom frmware DD-WRT on Linksys Router (YouTube)

At-a-Glance: OSI Model

Why should I Care About the OSI Model?

The OSI model serves as a guideline for creating and implementing network standards, devices, and internetworking schemes. Advantages of using the OSI model include the following:

• Breaks up interrelated aspects of network operation into less-complex elements.
• Enables companies and individual engineers to specialize design and development efforts on modular functions.
• Provides standard interfaces for plug-and-play compatibility and multivendor integration.
• Abstracts different layers of the network from each other to provide easier adoption of new technologies within a layer.

Develop mnemonics to help you memorize the layers and their order. Here's an example:

Please Do Not Throw Sausage Pizza Away

What Problems Need to Be Solved?

OSI layers can communicate only with the layer directly above or below it on the stack, and with its peer layer on another device. A process must be used so that information can be passed down the stack, across the network, and back up the stack on the peer device.