Computer Basics

Let’s test your knowledge of UDP, TCP, smurf attacks, EIGRP, and more with these questions designed to help you prepare for success on your CCENT, CCNA, CCNP, Network+, and Security+ certification exams! CCENT Certification / Network+ Certification: Which of the following protocols runs on both UDP and TCP? A. DHCP B. SNMP C. DNS D. ARP E. Inverse ARP Answer: C. DNS runs on port 53, both on TCP and UDP. Security+ Certification: Briefly define the term "smurf attack". (Not too briefly, though!) Answer: Basically, a smurf attack involves sends ICMP Echo packets (pings) with the intended victim's IP address specified as the source of the Echo packets. This transmission takes the form of a directed broadcast, which means that quite a few hosts can receive it - and then respond with ICMP Echo Replies, which will all be sent to the intended victim. CCNA Exam: R1 and R3 are directly connected at their respective Serial1 interfaces via a DTE/DCE cable. What command will tell you whether the interface is connected to the DTE or DCE end of the cable? Answer: Run show controller serial 1 on either router - the DTE / DCE information is near the top of the output. CCNP Certification / BSCI Exam: DUAL has discovered four possible paths to a remote network, with the following metrics: PathA, 1500. PathB, 1500. PathC, 2600. PathD, 3100. What command will allow EIGRP to use the first three paths without using the fourth? Answer: variance 2 would do the job. Any path with a metric of 3000 or lower will be utilized; setting it to 3 would bring PathD into the equation. CCNP Certification / BCMSN Exam: What is the main purpose of IEEE 802.3ac? Answer: The IEEE 802.3ac standard allows the maximum frame length to be extended to 1522 bytes, which means the dot1q 4-byte header doesn't cause problems in transmission. CCNP Certification / ONT Exam: Which queueing strategy gives priority to interactive, low-bandwidth communications by default? Answer: Weighted Fair Queueing (WFQ) gives priority to interactive, low-bandwidth conversations, and then splits the remaining bandwidth fairly among the remaining conversations. Look for a new set of Cisco and CompTIA certification exam questions soon!

More Cisco CCNA, CCENT, and CCNP candidates than ever before are putting together their own home labs for their certification exam study, and that's a great trend - there's nothing like learning on the real thing! Part of putting a home lab together is getting the right cables and understanding their usage. In this new Cisco home lab series, we'll take a look at the different cable types and how each fits into your home lab. The first cable type we'll look at is the multi-purpose DTE/DCE cable. When I say "multi-purpose", I mean that while the cable will always perform the same task, it can be used in several different points in your home lab network. If you're going to have a frame relay switch - and you should get one if at all possible, since having your own frame relay cloud is a tremendous boost to your home lab studies and your exam score - you're going to need a DTE/DCE cable. You can also use a DTE/DCE cable to directly connect two Cisco router serial interfaces and configure HDLC (the default) or PPP encapsulation over that point-to-point link. Most of today's DTE/DCE cables have "DTE" clearly stamped on one end of the cable - actually, "DTE" is probably embedded into the connector itself. Naturally, the other end will have "DCE" clearly indicated. It's the DCE end that will connect to your frame relay switch. If you're going to use a direct connection to run PPP or HDLC, it almost doesn't matter which end of the cable is connected to a given router. Keyword: "almost". You must use the clockrate command on the DCE end of the connection in order to bring the line protocol up. If you're not sure which end of your DTE/DCE cable is connected to a given serial interface, just use the show controller serial command to get that information. Most of the output of that command isn't comprehensible, but what we need is right on top: R3#show controller serial 1 HD unit 1, idb = 0x11B4DC, driver structure at 0x121868 buffer size 1524 HD unit 1, V.35 DCE cable Naturally, if it's the DTE end, you'll see "DTE" there. And if you don't have anything connected to that interface, you'll see "no cable". Whether you have your own frame relay switch or not, you'll want to pick up some DTE/DCE cables for direct connections between your Cisco home lab router's serial interfaces. Just don't forget to put the clockrate command on the DCE end of the cable! And if you're not familiar with a frame relay switch, check this same website soon for a tutorial that will show you how to set one up. Just about any Cisco router can serve as a home lab frame relay switch, and once you've got it configured, you're in good shape - but it can be a little maddening to get it up and running in the first place. I'll show you how to avoid that aggravation in the next installment of this Cisco home lab tutorial series!

Blogs are now an extremely popular and important part of the internet. Millions of people blog every day. As blogs have evolved over the years, so has the commenting system. Now anyone can make comments on a particular blog posting. As blog commenting has grown more popular, so has spam commenting. In this newsletter, we’ll go over why comments are a great form of feedback for your blog, how they help the credibility of your content, what spam comments are and how to prevent them from happening. Comments – A great form of feedback When blogs first came around, they were simply online journals. No one could post comments on a blog posting. That all changed in 1998 with OpenDiary, a site which allowed people to comment on blog postings. Now every blog, whether it is remotely or self-hosted, includes this option to comment. Commenting is great because it allows real people to tell you what they think about your form. It gives you feedback on what you are doing right and what you may need to improve. Comments can be encouraging to you and motivate you to post more quality blog messages. Or they can be constructive criticism to make you work harder to get better at writing content. Whatever the style of comment is, it is still very useful to your blog. High numbers of comments have the ability to make a blog look credible because they show that the blog is being read by a lot of people. That’s something that every blog owner wants, and comments help to let them know just how many people enjoy their content. Bad comments Unfortunately, spammers have now started to use comments as a way to spam. How do you know what a spam comment is? Well, a spam comment is a comment that only advertises another site or product. If the comment seems bland/generic with a cheap link thrown in, then it’s definitely a spam comment. Here is an example of a typical spam comment: “Hey, this site is really cool. Check out my really cool site at spamsite.com.” Of course not all spam comments will be this blatant, but you get the point. Fortunately for bloggers, as spam comments have grown, so has the ways to prevent it. Here are a couple ways that you can prevent spam comments from even being posted on your blog. #1: Close off commenting on older blog posts There are options for you to stop comments from being posted on any particular blog post. Lots of times, spammers will post comments in weeks or months old posts. So take away this opportunity from them to keep it from happening. Most blog hosters now offer this as a standard option in the tool panel. If one of your posts has been up for a couple weeks, close it up. #2: Take advantage of software offered to prevent comment spam If you host your own blog using WordPress, you can use an option in that software to prevent spam. Even if you aren’t using WordPress, you can still use other Spam comment blocking software like Spam Karma, Akismet, and Bad Behavior. While these aren’t 100% effective, they have proven to be quite effective in preventing spam from happening. #3: Take a look at your settings and see what can be tweaked to toughen your protection Lots of blogs now have settings to help prevent spam. If you already have a spam blocker on in your blog and are still experiencing spam, take a closer look at the settings to see if there’s anything that can be tweaked to make your protection stronger. However, if you do this, you should closely monitor your posts to make sure legit comments aren’t being blocked out. If they are, you might have to lighten up a bit. #4: Regularly read your blog comments Be sure to keep an eye on your comments. Even the best software or setting can’t prevent everything, so you will have to occasionally manually remove comments on your own. By applying the above principles, you can ensure that your blog is full of only good, quality comments, which will help your credibility tremendously. Comments are a great form of communication between yourself and your readers. They help the credibility of your blog!

Microsoft Windows is the name of several families of software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUIs). The most recent client version of Windows is Windows Vista. The current server version of Windows is Windows Server 2008. Windows 1.0 (1985) The first version of Windows provided a new software environment for developing and running applications that use bitmap displays and mouse pointing devices. Before Windows, PC users relied on the MS-DOS® method of typing commands at the C prompt (C:\). With Windows, users moved a mouse to point and click their way through tasks, such as starting applications. In addition, Windows users could switch among several concurrently running applications. The product included a set of desktop applications, including the MS-DOS file management program, a calendar, card file, notepad, calculator, clock, and telecommunications programs, which helped users, manage day-to-day activities. Windows 2.0 (1987) Windows 2.0 took advantage of the improved processing speed of the Intel 286 processor, expanded memory, and inter-application communication capabilities made possible through Dynamic Data Exchange (DDE). With improved graphics support, users could now overlap windows, control screen layout, and use keyboard combinations to move rapidly through Windows operations. Many developers wrote their first Windows–based applications for this release. Windows 3.0 (1990) The third major release of the Windows platform from Microsoft offered improved performance, advanced graphics with 16 colors, and full support of the more powerful Intel 386 processor. A new wave of 386 PCs helped drive the popularity of Windows 3.0, which offered a wide range of useful features and capabilities, including: Program Manager, File Manager, and Print Manager. A completely rewritten application development environment. An improved set of Windows icons. Windows NT 3.1 (1993) When Microsoft Windows NT® was released to manufacturing on July 27, 1993, Microsoft met an important milestone: the completion of a project begun in the late 1980s to build an advanced new operating system from scratch. Windows NT was the first Windows operating system to combine support for high-end, client/server business applications with the industry's leading personal productivity applications. Windows for Workgroups 3.11 (1993) A superset of Windows 3.1, Windows for Workgroups 3.11 added peer-to-peer workgroup and domain networking support. For the first time, Windows–based PCs were network-aware and became an integral part of the emerging client/server computing evolution. Windows for Workgroups was used in local area networks (LANs) and on standalone PCs and laptop computers. It added features of special interest to corporate users, such as centralized configuration and security, significantly improved support for Novell NetWare networks, and remote access service (RAS) Windows NT Workstation 3.5 (1994) The Windows NT Workstation 3.5 release provided the highest degree of protection yet for critical business applications and data. With support for the OpenGL graphics standard, this operating system helped power high-end applications for software development, engineering, financial analysis, scientific, and business-critical tasks. Windows 95 (1995) Windows 95 was the successor to the three existing general-purpose desktop operating systems from Microsoft—Windows 3.1, Windows for Workgroups, and MS-DOS. Windows 95 integrated a 32-bit TCP/IP (Transmission Control Protocol/Internet Protocol) stack for built-in Internet support, dial-up networking, and new Plug and Play capabilities that made it easy for users to install hardware and software. The 32-bit operating system also offered enhanced multimedia capabilities, more powerful features for mobile computing, and integrated networking. Windows NT Workstation 4.0 (1996) This upgrade to the Microsoft business desktop operating system brought increased ease of use and simplified management, higher network throughput, and tools for developing and managing intranets. Windows NT Workstation 4.0 included the popular Windows 95 user interface yet provided improved networking support for easier and more secure access to the Internet and corporate intranets. Windows 98 (1998) Windows 98 was the upgrade from Windows 95. Described as an operating system that "Works Better, Plays Better," Windows 98 was the first version of Windows designed specifically for consumers. With Windows 98, users could find information more easily on their PCs as well as the Internet. Other ease-of-use improvements included the ability to open and close applications more quickly, support for reading DVD discs, and support for universal serial bus (USB) devices Windows 98 Second Edition (1999) Windows 98 SE, as it was often abbreviated, was an incremental update to Windows 98. It offered consumers a variety of new and enhanced hardware compatibility and Internet-related features. Windows 98 SE helped improve users' online experience with the Internet Explorer 5.0 browser technology and Microsoft Windows NetMeeting® 3.0 conferencing software. It also included Microsoft DirectX® API 6.1, which provided improved support for Windows multimedia, and offered home networking capabilities through Internet connection sharing (ICS) Windows Millennium Edition (Windows Me) (2000) Designed for home computer users, Windows Me offered consumers numerous music, video, and home networking enhancements and reliability improvements. Windows Me was the last Microsoft operating system to be based on the Windows 95 code base. Microsoft announced that all future operating system products would be based on the Windows NT and Windows 2000 kernel. Windows 2000 Professional (2000) Windows 2000 added major improvements in reliability, ease of use, Internet compatibility, and support for mobile computing. Among other improvements, Windows 2000 Professional simplified hardware installation by adding support for a wide variety of new Plug and Play hardware, including advanced networking and wireless products, USB devices, IEEE 1394 devices, and infrared devices. Windows XP (2001) With the release of Windows XP in October 2001, Microsoft merged its two Windows operating system lines for consumers and businesses, uniting them around the Windows 2000 code base. With Windows XP, home users can work with and enjoy music, movies, messaging, and photos with their computer, while business users can work smarter and faster, thanks to new technical-support technology, a fresh user interface, and many other improvements that make it easier to use for a wide range of tasks Windows VISTA Windows Vista is a line of operating systems developed by Microsoft for use on personal computers, including home and business desktops, laptops, Tablet PCs, and media centers. Windows Vista contains many changes and new features, including an updated graphical user interface and visual style dubbed Windows Aero, improved searching features, new multimedia creation tools such as Windows DVD Maker, and redesigned networking, audio, print, and display sub-systems