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Enable Passwords On Cisco Routers Via Enable Password And Enable Secret

Fri, 30 May 2008 14:38:00 EST

Security is a part of every good technical administrator�s game plan. Luckily the good folks at Cisco have made the task of securitizing a Cisco router fairly straightforward in design- with support given for up to five types of passwords. Taking advantage of these passwords is vital to a network�s internal security, and should be [...]

How a Broadcast Address Works

Wed, 13 Feb 2008 17:16:00 EST

Imagine you�re Paul Revere, riding from Boston to Lexington to warn citizens that the redcoats were coming. He may not be as fast as computer networks today, but Paul Revere was essentially acting much like a broadcast would- he was relaying his message to the entire town of Lexington. A broadcast, in particular, is a simple message that is sent to all clients on a local area network. But just exactly what enables a network to broadcast a message to every single client on the network?

An Introduction to Dynamic Host Configuration Protocol

Mon, 04 Feb 2008 22:43:00 EST

Let�s imagine you�re a system administrator at a large company. You are implementing a new network of several hundred computers. All is fine and well until you realize: you have to manually input every single IP address, subnet mask, and gateway settings onto every single computer. You�re paid well, but maybe not that well. For those of us who don�t think many hours worth of data entry is fun, we turn to DHCP- or Dynamic Host Configuration protocol.

Securing Cisco Routers with IP Directed-Broadcast

Sat, 02 Feb 2008 22:43:00 EST

One of several overlooked commands that can produce a world of hurt for networks is the IP Directed-broadcast command. This command was introduced in Cisco�s routers at IOS version 10. Cisco soon realized that this command was being maliciously exploited in denial of service attacks, and action had to be taken- particularly against smurf attacks.

An Introduction to Cisco Router Configuration

Sat, 02 Feb 2008 12:38:00 EST

Configuring a router sounds like a tough task. Routers are capable of sending and routing data on a dynamic level- no easy feat. But with this article we are only getting our feet wet. We will take a look at how we connect to a router via the console port and setup a HyperTerminal session to configure the router directly.

CCNA 1 Module 8 Exam Solutions

Thu, 31 Jan 2008 16:57:00 EST

This set of solutions corresponds with our last update, where we released an article on Ethernet switching.

An Introduction to Ethernet Switching

Thu, 31 Jan 2008 09:12:00 EST

When you stop to think how well the internet is put together, you start to wonder how the internet coexists with all the chaos that results from broadcasts, data collision, and data loops. Yet, despite the odds, the internet is still (currently) alive and thriving today. But what can we attribute this achievement to? As you�ll find in the coming section, we owe a lot of gratitude towards a little something Cisco likes to call Ethernet switching.

CCNA 1 Module 7 Solutions

Wed, 30 Jan 2008 19:04:00 EST

Here is the latest round of Cisco answers. This content was covered in the CCNA 1 Module 6/7 exam, albeit a bit shorter. Also check out the support article on Ethernet history.

CCNA 1 Module 6/7 Solutions

Wed, 30 Jan 2008 17:04:00 EST

Here is the next chapter in our CCNA exam preps. We have also created "A Brief History of Ethernet" as a support article to go along with it. Be sure to check it out!

CCNA 1 Module 6 Answers

Tue, 29 Jan 2008 18:16:00 EST

Here it is: CCNA 1 Module 6 Answers, complete with explanations. We also created a backup article to support some answers, so you shouldn't have any problem getting this exam under your belt!

CSMA/CD Explained

Tue, 29 Jan 2008 15:13:00 EST

First thing is first: save yourself some trouble and remember that carrier sense multiple access collision detect is best referred to as simply CSMA/CD. We�ve heard some ridiculously long terms before, but CSMA/CD takes the cake.

CCNA 1 Module 5 Exam Solutions

Thu, 24 Jan 2008 16:14:00 EST

Here it is, as promised: the solutions and explanations to CCNA 1 Module 5 Exam questions. We'll be covering a lot of networking media, LAN, and WAN theory- don't worry, it's all thoroughly explained!

A Brief Overview Of Cabling LANs And WANs

Thu, 24 Jan 2008 01:11:00 EST

An overview of cabling LANs and WANs- a support article we released to help students with the exam preparation we are releasing within 24 hours. You'll notice the CCNA 1 Module 5 exam solutions will be published within this time frame- so keep a look out!

CCNA 1 Module 4 Exam Solutions

Tue, 22 Jan 2008 13:04:00 EST

Here it is- CCNA 1 Module 4 Exam solutions. Explained, and not just answers! This module covers a lot of information on cable testing, but as always, we have plenty of explanations and supporting articles to make it easy!

The Basics Of Network Cable Testing

Tue, 22 Jan 2008 00:40:00 EST

We just released an introductory guide to network cable testing, in preparation to release the CCNA 1 Module 4 exam solutions. Expect a new exam prep very soon!

CCNA 1 Module 3 Exam Solutions

Sun, 20 Jan 2008 14:36:00 EST

Here it is: The solutions to the third module of CCNA 1. Enjoy the guide!

CCNA 1 Module 2 Exam Solutions

Mon, 14 Jan 2008 21:38:00 EST

Here's the second round of solutions for Cisco's CCNA 1 exams. This time we take a look at Module 2 in particular. Hold on to your hats, we're taking a dive into LANs, TCP/IP, and the ever popular encapsulation process!

A Guide To Network Topology

Thu, 10 Jan 2008 15:14:00 EST

Although it is usually easier to start connecting wires and setting up your network, you�ll appreciate the level of organization topology models provide- especially when your network grows in size. And if you�re looking to do well on networking exams, consider these topologies essential to both learn and memorize.

CCNA 1 Module 1 Exam Solutions

Sat, 05 Jan 2008 14:28:00 EST

Cisco�s exams can be a lot of hard work- we know. But the worst thing you can do to yourself is to simply look up the answers to exam questions. Not only do you not learn anything- but you�re hurting your future in the process. If you want a helpful point in the right direction, be sure to keep this bookmarked.

A Guide To Network Math

Fri, 04 Jan 2008 14:36:00 EST

You are probably accustomed to using what is called decimal- the numbering system you�ve been learning since kindergarten. In networking we use three primary numbering systems: binary, decimal, and hexadecimal. It is direly important to know what each numbering system is for, and more specifically how to convert from one system to another. But don�t worry; it�s easier than you might think.

How The Application Layer Works

Tue, 01 Jan 2008 19:04:00 EST

In the previous section we reviewed several aspects of the Transport Layer. We learned a great deal of information; covering sockets, ports, TCP, UDP, segments, and datagrams. Now we will take a look at the fourth and final layer of the TCP/IP stack: the Application Layer.

How The Transport Layer Works

Fri, 28 Dec 2007 19:39:00 EST

In the previous section we took a look at the Internet Layer. We took apart the IP header information, reviewed IP addresses and routing information, and briefly discussed ARP and RARP technologies. Next in line we have the Transport layer- the layer responsible for actually getting the data packets to a specific location. When we receive email, we want to open it with our email program- not anything else. So how does a computer know exactly where to route data to appropriate programs, all while dealing with multiple connections?

What Is The Difference Between A Hub And A Switch?

Mon, 24 Dec 2007 18:06:00 EST

A hub and switch essentially accomplish the same thing, although their methods are different. Both can be used to regenerate degraded signals (acting as a repeater), and both can be used to split a signal into multiple signals (handy for splitting up an internet connection to your home network, for instance). But should you really care how they do it? If they both accomplish the same thing, what�s the difference?

How The Internet Layer Works

Wed, 19 Dec 2007 18:33:00 EST

In the previous section, we learned about the Network Access layer. Essentially we learned more about the anatomy of a frame, physical addressing, and what exactly the physical layer accomplishes. Don�t relax yet- we still have three layers to go!

How The Network Access Layer Works Within The Tcp/Ip Model

Thu, 13 Dec 2007 19:15:00 EST

Perhaps one of the most mysterious layers of the TCP/IP model is the Network Access Layer. It is the layer responsible for interfacing with your network�s architecture- something the everyday user can�t see. As we can�t physically interact with the Network Access Layer, how it works often eludes networking students.

How Encapsulation In The Tcp/Ip Model Works

Tue, 11 Dec 2007 17:15:00 EST

In the previous section we reviewed the TCP/IP and OSI model. For the sake of clarity, we will be using the TCP/IP model to demonstrate encapsulation, as compared to the OSI model. If you are still struggling with grasping concepts of the TCP/IP model you may wish to view the previous section once more. Otherwise, onward to the encapsulation process!

An Introduction To The Tcp/Ip And OSI Model

Tue, 11 Dec 2007 17:16:00 EST

In the previous section, we learned that TCP/IP is a suite of protocols and rules. It allows us to communicate with other computers and devices over a connection oriented network. What we didn�t cover was the TCP/IP and OSI model- which helps us understand the TCP/IP suite in a manner of layers and modules. In this section, we will look at the TCP/IP model and OSI model to get a better understanding of the communication process.

How to Subnet a Network

Mon, 03 Dec 2007 21:39:00 EST

A properly designed subnet can do wonders for the security and performance of a network. The main idea in subnetting is to divide a network into smaller pieces, which we call subnets. Actually implementing a subnet is typically more difficult than simply using the default subnet mask of 255.255.255.0. This usually means that temporary or smaller networks do not need to be subnetted.

Three Backdoor Programs Hackers Use to Control Your Computer

Mon, 03 Dec 2007 21:38:00 EST

There is a common misconception about security today, and it isn�t pretty. Most users would love to believe that their pricey consumer firewalls shield them from anything obscene- especially from outdated threats. The sad part is they couldn�t be more wrong. We seek to prove this with three separate programs that can compromise your computers security before you have a chance to say �What�s a backdoor?� And yes, these programs were created in the 1990's, but still pose as a valid threat today. Namely the first two, which are still being developed today.

How To Prevent Denial of Service Attacks

Mon, 03 Dec 2007 21:38:00 EST

The denial of service attack is statistically the most used malicious attack out of them all. This stems from the ease of use of the attack, as well as the alarming lethality. Literally anyone can bring down a website with a simple command prompt. The question is- how do you protect against an attack that can cripple your network or website in a matter of minutes?

An Introduction to TCP/IP

Mon, 03 Dec 2007 21:37:00 EST

TCP/IP , or Transmission Control protocol/Internet Protocol, is literally the backbone of internet and network communication. The concepts of TCP/IP are difficult to grasp without previous experience, so don�t be dismayed if it doesn�t click instantly. To better help you out, we�ll start from the very beginning- with a definition of just what a network is.

The Difference between Straight-Through Cables, Crossover Cables, and Rollover Cables

Mon, 03 Dec 2007 21:37:00 EST

There are generally three main types of networking cables: straight-through, crossover, and rollover cables. Each cable type has a distinct use, and should not be used in place of another. So how do you know which cable to use for what you need?

How Kerberos Authentication Works

Mon, 03 Dec 2007 21:33:00 EST

You may not know it, but your network is probably unsecured right now. Anyone with the right tools could capture, manipulate, and add data between the connections you maintain with the internet. Of course, the cat and mouse game of security isn�t one-sided. One of the authentication methods every network administrator should know about is Kerberos.