The Binary Code: 1s and 0s

It’s well known that computers transmit information digitally, using binary code: ones and zeros. This translates well to radio waves, since those 1s and 0s can be represented by different kinds of beeps. These beeps are so fast that they’re outside the hearing range of humans.

Morse Code: Dots And Dashes

It works like Morse code, which is a way to transmit the alphabet over radio waves using dots (short beeps) and dashes (long beeps). Morse code was used manually for years via telegraph to get information from 1 place to another very quickly. More importantly for this example, though, it is a binary system, just as a computer system is.

Wireless networking, then, can be thought of as a Morse code for computers. You plug in a combined radio receiver and transmitter, and the computer is able to send out its equivalent of dots and dashes (bits, in computer-speak) to get your data from here to there.

Wavelengths And Frequencies

You might wonder how the computer can send and receive data at high speed without becoming garbled nonsense. The key to wireless networking is how it gets around this problem.

First, wireless transmissions are sent at very high frequencies, which allows more data to be sent per second. Most wireless connections use a frequency of 2.4 gigahertz (2.4 billion cycles per second) — a frequency similar to mobile phones and microwave ovens. However, this high frequency produces a wavelength that is very short, which is why wireless networking is effective only over short distances.

Wireless networks also use a technique called “frequency hopping.” They use dozens of frequencies, and constantly switch among them. This makes wireless networks more immune to interference from other radio signals than if they transmitted on a single frequency.

Internet Access Points

The final step for a wireless network is to provide internet access for every computer on the network. This is done by a special piece of wireless equipment called an access point. An access point is more expensive than a wireless card for 1 computer, because it contains radios capable of communicating with around 100 computers, sharing internet access among them. Dedicated access points are necessary only for larger networks. With only a few computers, it is possible to use 1 of them as the access point, or to use a wireless router.

Industry Standards

Wireless equipment from different manufacturers can work together to handle these complex communications because there are standards which guide the production of all wireless devices. These standards are technically called the 802.11. Because of industry compliance with these standards, wireless networking is both easy to use and affordable today.

Wireless Is Simple To Use

If all this talk of frequencies has you worried — relax. Wireless networking hardware and software handle all of this automatically, without need for user intervention. Wireless networking, for all its complicated ability, is far simpler to use than you might expect.

Wireless Networks: How Do They Work? is a post from: Techno And Science News | At4k-12.org

Interference Checks

While it won’t stop a wireless network from working altogether, interference in its frequency range can slow it down significantly, as well as reducing its range. If something is causing interference, the first thing you’ll know about it is when your connection stops working — unless you know what to look for.

There are two very common causes of wireless interference: wireless phones and microwave ovens. 2.4Ghz, the most common wireless networking frequency, is also a commonly-used wireless phone frequency. It is possible, though, to find phones that use other frequencies. Microwave ovens, on the other hand, operate at around 2.4Ghz by definition. It should be alright to have devices like these in your house, but certainly not in the same room as any computer that you plan to use a wireless connection with.

Wall Construction

Wireless can, in theory, pass through walls and other partitions easily. In practice, though, some walls are more solid than others, which means that they are more likely to block some of the signal. Note that it’s only your interior partitions that matter, not the exterior ones. This does, however, include your floors, if you want the connection to work between levels.

Wireless does well with partitions made from: drywall, plywood, other wood (including doors), glass.

Wireless has trouble with: brick, plaster, cement, metal, stone, double-glazed glass.

Basically, it’s all to do with how porous the materials are — ones that let more of other things through also let more of your wireless signal through.

If you have a wall made of one of the ‘bad’ materials, it’s not the end of the world. It just means that your wireless connection might have a slower speed or a shorter range. You may want to spend more than you otherwise would to get better equipment and overcome this problem.

Decide Your Budget.

You need to stand back, take a look at your needs, and decide how much you’re going to spend. Do you have long distances to cover? Do you want your connection to go through stone walls? Each factor will help you decide how much you should be looking to spend — remember that the more problems you have, the more power you will need. On the other hand, if you live in a small wooden house, you can probably just go for the cheapest thing you can find.

Read Reviews.

It’s well worth searching a site like amazon.com for wireless equipment, and taking a look at people’s reviews to see what the different brands out there are like, and what you can get for your money. It is always a very bad idea to buy something without getting a second, third and fourth opinion, especially if you’re buying it online. If you can, try to get to a computer shop and see some wireless networking equipment in action before you commit yourself.

Install and Update Windows XP.

Finally, your wireless life will really be improved if you have the latest version of Windows. Because wireless is such a new technology, it wasn’t really around in any significant way back when Windows 98, ME and 2000 were released, and support for them wasn’t built in to the system. You’ll have a lot more trouble getting wireless to work on systems like these than you would on Windows XP.

Even if you’ve got Windows XP, though, that doesn’t solve the problem entirely. Windows XP Service Pack 2 (an updated version of Windows XP) contains much easier-to-use tools for configuring and using wireless than the un-updated versions do. If you’ve been using your copy of Windows for a while without updating it, you should really make sure you’ve got all the latest updates from http://windowsupdate.microsoft.com before you go any further.

Wireless Installation Checklist is a post from: Techno And Science News | At4k-12.org

Whats need in the package is a camera to fit either just outside the front or back door that transmits a wireless signal. The best one to buy would be one that has night vision to ensure you can see everything at night. The second would be a receiver. Some receivers have screens so you can watch whats going on no matter where you are and others need to be connected to a computer or television to see the transmission.

If connected to a computer or television the live feed from the camera can be directly recorded to a hard drive or a cassette or DVD depending on which is convenient. Several cameras can be implemented to get several signals meaning more coverage of the home and the surrounding area.

These wireless home security packages are common and can be purchased at most electronics stores. They are on the expensive side but are worth the purchase for the kind of technology it has. With almost everything becoming wireless these days it was only a matter of time until cameras became wireless also.

Most people need some sort of security measure in place, not for protection, but for peace of mind that they are safe in their home. Although there are several other measures that can be implemented in terms of security, the wireless home security camera is a valuable tool for keeping an eye on things at all times. It will complement any other security measure you have in place and will not disappoint.

Wireless Home Security Camera is a post from: Techno And Science News | At4k-12.org

Following is the description of all logical components of the Active Directory structure:

Forest: A forest is the outermost boundary of an Active Directory structure. It is a group of multiple domain trees that share a common schema but do not form a contiguous namespace. It is created when the first Active Directory-based computer is installed on a network. There is at least one forest on a network. The first domain in a forest is called a root domain. It controls the schema and domain naming for the entire forest. It can be separately removed from the forest. Administrators can create multiple forests and then create trust relationships between specific domains in those forests, depending upon the organizational needs.

Trees: A hierarchical structure of multiple domains organized in the Active Directory forest is referred to as a tree. It consists of a root domain and several child domains. The first domain created in a tree becomes the root domain. Any domain added to the root domain becomes its child, and the root domain becomes its parent. The parent-child hierarchy continues until the terminal node is reached. All domains in a tree share a common schema, which is defined at the forest level. Depending upon the organizational needs, multiple domain trees can be included in a forest.

Domains: A domain is the basic organizational structure of a Windows Server 2003 networking model. It logically organizes the resources on a network and defines a security boundary in Active Directory. The directory may contain more than one domain, and each domain follows its own security policy and trust relationships with other domains. Almost all the organizations having a large network use domain type of networking model to enhance network security and enable administrators to efficiently manage the entire network.

Objects: Active Directory stores all network resources in the form of objects in a hierarchical structure of containers and subcontainers, thereby making them easily accessible and manageable. Each object class consists of several attributes. Whenever a new object is created for a particular class, it automatically inherits all attributes from its member class. Although the Windows Server 2003 Active Directory defines its default set of objects, administrators can modify it according to the organizational needs.

Organizational Unit (OU): It is the least abstract component of the Windows Server 2003 Active Directory. It works as a container into which resources of a domain can be placed. Its logical structure is similar to an organization’s functional structure. It allows creating administrative boundaries in a domain by delegating separate administrative tasks to the administrators on the domain. Administrators can create multiple Organizational Units in the network. They can also create nesting of OUs, which means that other OUs can be created within an OU.
In a large complex network, the Active Directory service provides a single point of management for the administrators by placing all the network resources at a single place. It allows administrators to effectively delegate administrative tasks as well as facilitate fast searching of network resources. It is easily scalable, i.e., administrators can add a large number of resources to it without having additional administrative burden. It is accomplished by partitioning the directory database, distributing it across other domains, and establishing trust relationships, thereby providing users with benefits of decentralization, and at the same time, maintaining the centralized administration.

The physical network infrastructure of Active Directory is far too simple as compared to its logical structure. The physical components are domain controllers and sites.

Domain Controller: A Windows 2003 server on which Active Directory services are installed and run is called a domain controller. A domain controller locally resolves queries for information about objects in its domain. A domain can have multiple domain controllers. Each domain controller in a domain follows the multimaster model by having a complete replica of the domain’s directory partition. In this model, every domain controller holds a master copy of its directory partition. Administrators can use any of the domain controllers to modify the Active Directory database. The changes performed by the administrators are automatically replicated to other domain controllers in the domain.

However, there are some operations that do not follow the multimaster model. Active Directory handles these operations and assigns them to a single domain controller to be accomplished. Such a domain controller is referred to as operations master. The operations master performs several roles, which can be forest-wide as well as domain-wide.

Forest-wide roles: There are two types of forest-wide roles:

Schema Master and Domain Naming Master. The Schema Master is responsible for maintaining the schema and distributing it to the entire forest. The Domain Naming Master is responsible for maintaining the integrity of the forest by recording additions of domains to and deletions of domains from the forest. When new domains are to be added to a forest, the Domain Naming Master role is queried. In the absence of this role, new domains cannot be added.

Domain-wide roles: There are three types of domain-wide roles: RID Master, PDC Emulator, and Infrastructure Master.

RID Master: The RID Master is one of the operations master roles that exist in each domain in a forest. It controls the sequence number for the domain controllers within a domain. It provides a unique sequence of RIDs to each domain controller in a domain. When a domain controller creates a new object, the object is assigned a unique security ID consisting of a combination of a domain SID and a RID. The domain SID is a constant ID, whereas the RID is assigned to each object by the domain controller. The domain controller receives the RIDs from the RID Master. When the domain controller has used all the RIDs provided by the RID Master, it requests the RID Master to issue more RIDs for creating additional objects within the domain. When a domain controller exhausts its pool of RIDs, and the RID Master is unavailable, any new object in the domain cannot be created.

PDC Emulator: The PDC emulator is one of the five operations master roles in Active Directory. It is used in a domain containing non-Active Directory computers. It processes the password changes from both users and computers, replicates those updates to backup domain controllers, and runs the Domain Master browser. When a domain user requests a domain controller for authentication, and the domain controller is unable to authenticate the user due to bad password, the request is forwarded to the PDC emulator. The PDC emulator then verifies the password, and if it finds the updated entry for the requested password, it authenticates the request.

Infrastructure Master: The Infrastructure Master role is one of the Operations Master roles in Active Directory. It functions at the domain level and exists in each domain in the forest. It maintains all inter-domain object references by updating references from the objects in its domain to the objects in other domains. It performs a very important role in a multiple domain environment. It compares its data with that of a Global Catalog, which always has up-to-date information about the objects of all domains. When the Infrastructure Master finds data that is obsolete, it requests the global catalog for its updated version. If the updated data is available in the global catalog, the Infrastructure Master extracts and replicates the updated data to all the other domain controllers in the domain.

Domain controllers can also be assigned the role of a Global Catalog server. A Global Catalog is a special Active Directory database that stores a full replica of the directory for its host domain and the partial replica of the directories of other domains in a forest. It is created by default on the initial domain controller in the forest. It performs the following primary functions regarding logon capabilities and queries within Active Directory:

It enables network logon by providing universal group membership information to a domain controller when a logon request is initiated.

It enables finding directory information about all the domains in an Active Directory forest.

A Global Catalog is required to log on to a network within a multidomain environment. By providing universal group membership information, it greatly improves the response time for queries. In its absence, a user will be allowed to log on only to his local domain if his user account is external to the local domain.

Site: A site is a group of domain controllers that exist on different IP subnets and are connected via a fast and reliable network connection. A network may contain multiple sites connected by a WAN link. Sites are used to control replication traffic, which may occur within a site or between sites. Replication within a site is referred to as intrasite replication, and that between sites is referred to as intersite replication. Since all domain controllers within a site are generally connected by a fast LAN connection, the intrasite replication is always in uncompressed form. Any changes made in the domain are quickly replicated to the other domain controllers. Since sites are connected to each other via a WAN connection, the intersite replication always occurs in compressed form. Therefore, it is slower than the intrasite replication.

Windows Server 2003 Active Directory and Network Infrastructure is a post from: Techno And Science News | At4k-12.org

URL stands for Uniform Resource Locator. It’s the posh technical term for a web address. Web addresses normally take the form http://www.somesite.com/somepage.html, which is not too much of a problem. But some site names can get very long, and so can page names. The increased use of database-driven sites mean that URLs can get very long indeed, and most of them is computer gobbledygook. They are impossible to type in, if you are reading them in a print article, and often get corrupted by word-wrapping when they appear in an email or blog posting.

An URL shortener is a web service that takes a long address that’s hard to type, and turns it into a short one. You should use them in articles for print publication, classified ads, emails, blog and forum postings, anywhere there is a danger that the full address may be corrupted, or that someone may need to type the address into a browser manually.

But there is a danger in using short URLs that may make people afraid to use them. The short address disguises the real destination. This makes it easy for somebody to post an innocent looking message encouraging people to click on a link that takes them to a site which infects their computer with spyware, or something equally undesirable.

Some URL shortening services have tried to address this problem. The most well-known service, TinyURL.com, has an optional preview page that shows you the target address before you go there. But you have to know to type “preview” in front of the address, or visit the site and set it as a permanent option. Those who don’t know about this are still vulnerable to deception.

A safe URL shortener would not allow the creation of links to undesirable sites. It would also always display a preview page, so the user always sees where the link is taking them before they go there. xaddr.com uses Internet blacklists to prevent its use to disguise sites that are advertised by spam. Its preview page offers a link to McAfee’s Site Advisor, which can be used to check the safety of the destination.

Next time you need to write a long web address, use an URL shortener. But to encourage confidence that no harm will come from clicking the link, pick a safe one.

Why use URL shorteners? is a post from: Techno And Science News | At4k-12.org

When we try to find information everyday, most of us might go to Google.com. Yes, it’s true. Most of the time, Google works well. But does Google return the best information? I guess you would agree that the search engine’s ranking algorithm could only give a good answer, but not the best. Well, you may ask, where can I get the BEST? The best weather information? The best book information? The best price for your favorite mp3 player? The short answer is from the brain, from the hand picked information. Therefore, Navino’s editors and their users give out that the best weather website is weather.com, the best book website is amazon.com and the best price information is froogle.

Besides best hand picked information resources, Navino also provide the search engine gateway technology. Using this technology, you can search all the best website at Navino. All you need to do is to add a unique search name before your searching keywords.

For example, if you want to search New York’s weather, you can search with weather New York’ and you will be forwarded to weather.com with the keyword New York’. If you want to search finance books, you can search with book finance’ and you will be forwarded to amazon.com with the keyword finance’. If you want to search the best price for your favorite mp3 player, you can search with price mp3 player’ and you will be forwarded to froogle with the keyword mp3 player’.

Navino search engine gateway is very convenient for your everyday web surfing. Besides that, Navino also provides its users to customize their own search engine gateway and allows its users to recommend search names for public use.

What is search engine gateway? is a post from: Techno And Science News | At4k-12.org

Because a web browser can run on any type of computer, the need to maintain multiple paper copies of documents that are constantly changing can be eliminated. Documents like training manuals, internal phone books, procedure manuals, benefits information, employee handbooks, requisition forms, etc. can be maintained as electronic documents and updated at almost no cost. The savings in paper and other material costs can be significant

But the most powerful aspect of an intranet is its ability to display information in the same format to every computer being used. That allows all of the different software and databases a company uses to be available to all employees without any special equipment or software being installed on their systems.

This universal availability of information is sparking an era of collaboration unlike anything ever seen before. The departmental barriers that exist in many companies are slowing breaking down because now colleagues can share information readily using the company intranet.

Options for implementing an intranet

There are a variety of options for setting up an intranet. They include building your own intranet technology, purchasing and installing third-party software, or purchasing access through an extranet ASP. Here is a quick summary of the advantages and disadvantages of each approach:

1. Building it yourself
Advantages: Complete control of user interface design; ability to customize level of functionality; integration into internal systems, and direct access to user activity.

Disadvantages: High up-front development cost; requires staff expertise in the development of extranets, commitment of internal staff for 6 months to a year for planning, execution, review and implementation; and an ongoing commitment of internal staff for internal and client support, hosting, maintenance and upgrades.

2. Purchasing/installing third-party software
Advantages: Proven track-record of packaged solution; ability to choose functions and to
customize user interface, more rapid implementation compared to building it yourself.

Disadvantages: High up-front purchase cost; commitment of internal staff for customization and implementation; on-going commitment of internal staff for internal and client support, hosting, maintenance and upgrades; and extensive internal and client training

3. Using a Service Provider (ASP)
Advantages: Proven track-record of the application; low cost of entry and predictable cost over time; virtually immediate implementation; no commitment of internal staff for internal support, hosting, or maintenance; and upgrades at no cost by extranet experts, and savings on internal server use.

Disadvantages: Less freedom in user interface design, and fixed functionality.

In the final analysis
The approach you choose depends on how you work, the technical and financial resources at your disposal, and how rapidly you need to move forward.

What Is An Intranet? Definition and Uses… is a post from: Techno And Science News | At4k-12.org

Every network that has an internet connection is at risk of being compromised. Whilst there are several steps that you can take to secure your LAN, the only real solution is to close your LAN to incoming traffic, and restrict outgoing traffic.

However some services such as web or FTP servers require incoming connections. If you require these services you will need to consider whether it is essential that these servers are part of the LAN, or whether they can be placed in a physically separate network known as a DMZ (or demilitarised zone if you prefer its proper name). Ideally all servers in the DMZ will be stand alone servers, with unique logons and passwords for each server. If you require a backup server for machines within the DMZ then you should acquire a dedicated machine and keep the backup solution separate from the LAN backup solution.

The DMZ will come directly off the firewall, which means that there are two routes in and out of the DMZ, traffic to and from the internet, and traffic to and from the LAN. Traffic between the DMZ and your LAN would be treated totally separately to traffic between your DMZ and the Internet. Incoming traffic from the internet would be routed directly to your DMZ.
Therefore if any hacker where to compromise a machine within the DMZ, then the only network they would have access to would be the DMZ. The hacker would have little or no access to the LAN. It would also be the case that any virus infection or other security compromise within the LAN would not be able to migrate to the DMZ.

In order for the DMZ to be effective, you will have to keep the traffic between the LAN and the DMZ to a minimum. In the majority of cases, the only traffic required between the LAN and the DMZ is FTP. If you do not have physical access to the servers, you will also need some sort of remote management protocol such as terminal services or VNC.

Database servers

If your web servers require access to a database server, then you will need to consider where to place your database. The most secure place to locate a database server is to create yet another physically separate network called the secure zone, and to place the database server there.
The Secure zone is also a physically separate network connected directly to the firewall. The Secure zone is by definition the most secure place on the network. The only access to or from the secure zone would be the database connection from the DMZ (and LAN if required).

Exceptions to the rule

The dilemma faced by network engineers is where to put the email server. It requires SMTP connection to the internet, yet it also requires domain access from the LAN. If you where to place this server in the DMZ, the domain traffic would compromise the integrity of the DMZ, making it simply an extension of the LAN. Therefore in our opinion, the only place you can put an email server is on the LAN and allow SMTP traffic into this server. However we would recommend against allowing any form of HTTP access into this server. If your users require access to their mail from outside the network, it would be far more secure to look at some form of VPN solution. (with the firewall handling the VPN connections. LAN based VPN servers allow the VPN traffic onto the network before it is authenticated, which is never a good thing.)

Web Servers and Firewall Zones is a post from: Techno And Science News | At4k-12.org

The answer, unfortunately is not simple. This is because while many companies demand a certain certification, they will also bend the requirement and allow you to get certified once you have the job. There’s also people in the marketplace who are strong proponents of certification or another. The reason for this is usually because they have that certification and by requiring it, they somehow believe it validates their decision to obtain the training and pass the tests.

The reality is that like a good resume and education pedigree, certifications help get you in the door. Think about it for a moment. If you were hiring a network administrator, you would probably ask for the usually experience and basic education and some type of networking certification. If 100 people claiming the same skills and experiences levels all apply and all have at least the single required certification while 10 have not only the network cert but also maybe several MS and a security certificate, which candidates applying would probably get scheduled for interviews? Right! It would be the ones with the better paper qualifications.

So the value of a certification can be measured by it’s recognition as important by employers, and the relative value they place on such training. If you’re applying in network shops that value certifications, then they will naturally place a premium on the fact that your have that training and will probably reflect that in an increased earnings range.

The real key however is to recognize that employers are NOT employing you because you have a certification. You must have the skills necessary to do the job and meet the requirements of the position. No amount of certifications can make up for a strong work ethic and solid experience. With today’s study materials, almost anyone can learn enough to pass the required tests and become certified. This however does not make anyone competent to work on a network anymore than walking into a garage makes one a mechanic. It’s skills, talent and knowledge that are truly desired.

Microsoft Certifications are one of the most widely pursued and acclaimed professional certifications in the IT industry. Preparing MS certification tests, however, is a significant undertaking whether you’re just out of college or have been in IT field for years. IT professionals are continuously demanded to acquire new knowledge in order to perform well on their jobs as new technology in the IT industry emerged at a pace that has never been seen before. Regardless what certifications (Microsoft Certified Professional or MCP, Microsoft Certified System Administrator or MCSA, Microsoft Certified System Engineer or MCSE ) you are pursuing, a thorough planning will increase the chance of success.

The importance of hands-on Experience, no matter if it’s your own little network at home or at your job, experience matters! Being able to apply the knowledge gained by the study necessary to obtain your certification is just as important as the exam itself.

When preparing for any certification test, have a network available to physically learn the principles being taught. You network might only be a couple of old PC’s and a switch but it’s enough to understand the principles and basic information. You gain valuable skills that cannot be obtained any other way except through hands on work.

Finally, consider using CBT’s or computer based training as part of your test preparation. These tools are a great way to take your level of understanding to a new level. This is also true of practice exams.

If you develop the skills necessary to support the certifications, all your training, costs and effort will pay off handsomely. With your knowledge and training, you can expect to be have an easier time getting considered for positions, moving up in a company, and enjoying a solid work career.

Valuing Network Certifications – Is The Time, Money And Effort Worth The Bother? is a post from: Techno And Science News | At4k-12.org

Whats my IP and what do its numbers stand for?
IP stands for Internet Protocol and the address is formed from 4 numbers separated by periods. The IP address format is a 32 bit numeric one and each number can be from 0 to 255. The IP address consists of two parts: first one represent the network number and it is similar for more than one user (like the number of a street) and second represents the host name which is different for each user (like the house number). To increase the number of available IP addresses within big networks with a lot of users or small networks with few hosts, the address is divided into 4 classes (A, B, C, and D)

Having an IP address its like having a last name in a network. To identify a computer in a network (LAN-local area network, WAN-wide area network or on the Internet) it has to have an IP address. This number is similar to a phone number or to a zip code. It is unique and without it the device or computer can not be used in a network area. Within an isolated network the computers can be assigned different random IP addresses, but if a private network needs to be connected to the Internet the IP has to be registered so that its uniqueness is verified.

Where do I find my IP address?
Connect to a site that recognizes your IP address and let you see it also. You can visit this site for example: iprelated.com. These IP Lookup sites are very easy to use and very useful for others. An IP address can offer a lot information about the person who logs in on the Internet and engages in a certain activity.
This is how illegal activity is sometimes detected and violations are reported. The IP address says less about the user if it is a dynamic one because it changes every time the user logs in.
Another interesting aspect is that some people who have the information from your IP address are interested in taking you computer over and using its resources. This is not impossible! They can use software that enables them to do this so it is better to hide your IP when you are online.

Who gives me my IP address?
The IP address can be static or dynamic, meaning it can be the same every time you are online or it can change. The IP address is provided by a server through a service called DHCP (Dynamic Host Configuration Protocol)

Although things can get pretty complicated when explaining numbers and their significance, this is just a small and easy to understand introduction about the IP address that does not involve technical terms. The importance of these details is very high because starting from these brief explanations one can truly comprehend the necessity and implications of the IP address and of virtual geo location.

Theres no mystery in the IP address! is a post from: Techno And Science News | At4k-12.org