Networks Analyzed @ Netralized

Ip addresses consist of two parts, Network and Host part. Take for example the Ip address 172.16.1.1

What is the Network part and what is the Host part of an Ip address?

You can’t tell before assigning a subnet mask for the specific Ip address. By using a subnet mask we can distinguish the network and the host portion of the Ip address. The 255 part of the mask shows the network and the 0 part shows the host.

When we are given an Ip address and a subnet mask, we can discover the network address, the broadcast address, the first valid host Ip address and the last valid host Ip address of our network.

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VPN (virtual private network) is a tunneling method that gives us the capability to connect two remote sites together over the public WAN.

VPN allows us to connect to our local network from remote locations. For example let’s say that we have a company with two sites, one central office in California and one branch office in Texas. Some of the available methods for establishing a connection between them are: leased line, frame relay and ATM. But from the cost point of view none of these methods has the efficiency of VPN tunnels. You can establish a VPN tunnel even by using a cheap DSL connection.

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Ip addressing is a vital knowledge for all the IT and non IT people that are involved with networks, from large enterprise networks to small home networks.

To fully understand Ip addressing it’s necessary to be familiar with binary mathematics and conversions, from the decimal mathematic system to binary and vise versa. I will try to present you an easy procedure that can be used when doing conversions.

Binary to decimal

Binary numbers that are associated with Ip addressing always have eight digits (I like to call these digits “spaces”).
For example the number 11010101 as you can see is an eight digit number.
Now let’s try to convert this number into decimal:

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Every ip address belongs to a specific class.
The ip address classes are:

But how is an Ip address related to a class?

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When I start or finish a CCNA course I ask my students what they would like to know about the CCNA exam. Always there is some information that they would like to know but never thought to ask. So giving you all the necessary guidelines about the exam from the questions that the attendants of my courses had during my lectures about CCNA, would be a great idea!

First you can schedule to take the CCNA exam in every cisco certified learning center in your area. For more information, check the “Link” and then click “Academy and Class Search”. The exam has 50 to 60 questions and the participants have 90 minutes to answer them. All the examination process takes place in front of a Computer using a web interface. This might be a little bit tricky especially if this is your first time taking the exam. Getting familiarized with the interface will help a lot; some exam simulators can help you achieve that. Be careful because when you answer a question, the button that takes you to the next question becomes active; if you left click it will take you to the next question but you can’t go back to the previous one, so you have to be sure about your answer before moving forward to the next one.

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Nowadays a lot of people talk about DSL but what exactly is the DSL technology?

In this article I will try to give you a very brief overview about DSL and how it works.

DSL (Digital Subscriber Line) is an OSI layer 1 technology that allows you to deliver extra bandwidth and high speed data connections over a copper wire pair that is typically used for phone connections. This technological breakthrough is based on the research of Bell Labs that several years ago identified that a typical conversation on the telephone only uses a small frequency range of the available frequency spectrum (from 300HZ up to 3KHZ). That leaves all the other frequencies range up to 1MHZ, free to be used for other services.
Therefore, DSL uses our existing phone lines with very few changes from the phone company side, giving us extra services.

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Cisco systems has announced changes in the course material and the certification path of the CCNA exam.

First of all, the CCNA exam was constituted from two different courses INTRO and ICND. Now, Cisco has replaced the INTRO (32 hours) course with ICND 1 (40 hours) course and the ICND has been replaced by ICND 2 (40 hours) course.

The course materials and the changes - or should I say the updates that Cisco made - are: ICND 1 has almost the same topics with INTRO. Exception is Module 3 that is an introduction of wireless networking.

In the list below you can see analytically all the topics of ICND 1.

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Many of us have a DSL connection at home. Most of us can configure the DSL router by our selves and most of us can even port forward the ports that are needed. But do we really know why and when it is needed to be done?

Let’s say we have a DSL connection installed at our house or our business. We have three computers, all getting Internet from the same router with Ethernet or wireless connections. Let’s also suppose that we have a web server installed on one of the three computers listening to TCP port 80.

When someone from the Internet tries to access our web server, his browser sends a request at port 80, but our router doesn’t know to which computer the request should be forwarded, since all three of them have the same Internet IP address. As a result, the host (our web server) becomes unreachable.

When we do port forwarding, we assign to the router instructions that when someone from the internet requests information from a specific port (80 in our case), the request should be forwarded to a specific computer identified by its local IP address, 192.168.xxx.xxx for example. The local IP, that the computer hosting the web server has, is usually assigned from the DHCP of the router. Therefore, when someone asks information on that port, router forwards the traffic automatically to the specified computer based on the information we’ve entered to the router.

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Welcome to our new website, Netralized.com. The idea started when two persons, Jim Skenderlis and Angelos Papaioannidis, met each other at some Cisco CCNP courses. Jim was an instructor and Angelos a course student. The aim of this article is not to describe our selves, that information can be found in the “about us” page inside the website, but to give you a “taste” of what the site is about and how it has been created. To make the long story short, Angelos got together with Jim and after some hours of talking, decided to make a web site about networks. The idea is simple; we have passion for what we both do and love to spread the word about it. Jim is a network professional that loves websites and Angel was into web development and promotion but at the same time, loved networks… What better combination could somebody ask for?

Domain name was our first milestone and we believe it was successfully overcame. Netralized came to our minds after thinking about “Networks Analyzed”. It felt good mixing up those two words and create a new one. After all, that’s what we’ll do. Combine information and knowledge and analyze it for our readers.

The aim of this web site is to make network professionals, network students and, in general, people who like to get new knowledge and information about networks, get involved. It would be awesome if some people start their day by drinking their morning coffee and read our latest article. Not only because they will learn about something new (hopefully), but also because they will hear a different approach, a different opinion about it.

After all, feedback is what’s driving us to make this site a better place for persons involved or interested in networks. Please, send us your thoughts, ideas or suggestions at info@netralized.com or through the “contact form” and make this site, your site.

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