Why Do You Always Feel So Tired?
Do you drag yourself through the day feeling drained and exhausted? Yes, we’re talking about lethargy, that heavy-lidded feeling that threatens to overpower you in the afternoon; that I-don’t-feel-like-working mood when you have a pile of reports to file. So what is it that’s making you want to curl up in bed? Lack of energy could stem from emotional stress, boredom, lack of sleep, and sometimes an upset hormonal cycle. It could also be due to a disruption in melatonin production.
What is melatonin, you ask? Melatonin is a hormone that helps travelers to sleep when they fly across different time zones. It is secreted by the pineal gland and is responsible for inducing sleep at night and governing the lowering of your core body temperature. The pineal gland slows its production of melatonin during daylight hours to keep your alert and increases its production when darkness falls. Melatonin starts to increase at about 9pm and peaks at around 2am. Any disruption to this cycle can affect sleep causing tiredness.
It is normal to feel a lack of energy, or be tired or drowsy sometimes. But if you’re tired even though you are sleeping more, exercising, eating better, and managing stress, you should consult a doctor. If you wake up in the morning rested but rapidly develop fatigue with activity, you may have a ongoing physical condition like an under-active thyroid. On the other hand, if you wake up with a low level of energy and have fatigue that lasts through the day, you may be depressed.
There are a few different types of energy and tiredness. There’s tense tiredness, tense energy, calm tiredness and calm energy. Tense energy is when you are revved up and doing lots of work but you’re not necessarily at your best. Calm tiredness is fatigue without stress, which can actually be pleasant at times such as before bedtime. The optimum is calm energy, or what people call “flow” or “being in the zone”. It is energy without tension, and is a sought-after state because you’re productive and completely focused.
The one to watch out for is tense tiredness. Your mood is low, you’re stressed, and you want something that will comfort you. Your mood is low, you’re stressed, and you want something that will comfort you. For many of us, that translates into chocolate, potato chi[s, and biscuits. It’s a vicious cycle. Your body has no oomph when you top it up with cheap fuel. In fact, you feel more tired and frustrated, and snack even more to feel better.
Let go of the calorie-rich, energy-poor binging for these guilt-free-pick-me-ups:
Exercise:
People who rely on candy bars rather than exercise feel more tense 60 minutes later while 10 minutes of brisk walking raised energy levels for one to two hours. Exercising regularly can increase your energy capacity. Do it three times a week for at least 15 minutes per session. You should be reasonably breathless during the workout for an indication that you’re exercising enough.
Naps:
If you stay up past midnight and wake yo as early as 7am, you’re not getting the minimum requisite of eight hours of sleep. Entire nations are suffering an energy slump as some people cram more and more things into their schedule. Our whole society has been speeding up – we’re working more and sleeping less, and that ends up making us eat more and exercising less. The panacea is, without a doubt, more sleep. The trick is knowing how much to nap and a half-hour nap may help. Your brain needs 10-15 minutes to drift into the sleep phase. Anything shorter won’t help and may leave you feeling worse. Why do we need sleep? The easiest way to understand why we sleep is to look at what happens when we don’t.
Sleep deprivation experiments have shown that after 14 days without sleep, rats will keel over and die. Three days of no shut-eye sees humans confused forgetful and hallucinatory. Sleep is vital because it helps our body to recover.
Music:
Listening to something you enjoy can raise energy level and reduce stress. But it is important to keep the volume down so it won’t be distracting. A low, background level is conducive.
Environment:
Your office could be sapping you of energy. Sick office syndrome can cause lethargy. Factors such as poor ventilation, lighting, and temperature (the ideal range is 20 to 23degrees Celsius) all play a part. Glare from the computer monitor can cause you feel drowsy. To energize your workstation, adjust the position of your monitor to reduce glare. Another option is a desk lamp to get rid of shadows being cast by lights not positioned directly above you.
Vitamins:
The right vitamins may help. Depression and fatigue can result from the body’s depletion of B vitamins, which can occur from stress or drinking too many caffeinated beverages. Other vitamins like C and E, help prevent fatigue by bolstering your immune system. Zinc is another energy booster which works by improving muscle strength and endurance.
Diet:
Why the perpetual drowsiness? This has got to do with what you eat. Our food are deficient in nutrient content. Due to modern farming practices, it is almost impossible to receive all the nutrients we need from our food and water supply because of pollution and contamination. While vitamins can reverse some of the damage, eating the right foods is very important. Here are some recommended energy boosters:
Concord grape juice (152 calories, 0g fat per cup): Enhances memory and problem solving skills by increasing dopamine in the brain. High in protective antioxidants.
Soy milk (127 calories, 5g fat per cup): Speeds learning ability and boosts memory (but mostly for women… ladies, take note!) most likely due to the phyto-oestrogen it contains.
Raisins (78 calories, 0g fat is 50 raisins): Contain boron, which may sharpen memory, and inrease mental alertness and reaction time.
Spinach (41 calories, 0.5g fat per up cooked): Loaded with lutein and other antioxidants that protect brain cells.
Blueberries (83 calories, 0g fat per cup): May increase brain-cell production in the hippocampus, the area of the brain that regulates memory.
How to Fix RPC Error When the RPC Server is Unavailable
Have you gotten an RPC error lately? They look a little like this:
- “RPC Server is Unavailable”
- OR “The RPC Server is too busy to complete the task”
- Here’s the best one, “Access denied”
This is fun stuff. Unfortunately, an RPC error is one of the most common errors out there, and most of us don’t even know what RPC is.
What is RPC?
RPC stands for “Remote Procedure Call.” This probably still doesn’t tell you much. Let’s see if we can put this in non-technical language. RPC is the go between of your computer and server. This is what allows your computer to access a network.
RPC has two main parts to it: the client and the server. When the client (the program requesting something) sends a message to the server (the process that takes the order or performs the task), it is being asked to execute a certain procedure. The client waits for the server to process the call before resuming the execution.
Why Won’t the RPC Server Work?
Usually, the RPC error pops up because there is some sort of miscommunication between the computer and the server. Most of the time, the wires get crossed somewhere due to Internet components that are not configured or activated. Sometimes it is just a matter of adjusting the Internet Firewalls or Proxy Server.
Quick RPC Error Fix
One way to investigate an RPC server error is to verify that you have enabled the DCOM Tunneling is enabled and not being blocked by any third party Internet Security programs such as AVG, Norton, McAfee, etc.
To do this:
1. Go to Start and Run
2. Type in DCOMCNFG
3. Click on Component Services
4. Click on Computers
5. In Computers, right click My Computer
6. Choose Properties
7. Go the Default Properties tab
8. Check the “Enable DCOM” tab
9. Go to the Default Protocols tab
10. Click Add
11. By the Protocol Sequence move the down arrow to Tunneling TCP/IP
12. Click OK
13. Click MoveUp button until Tunneling is at the top of the list
14. Now you may select SPX and Remove
15. Click OK or close the program out
16. Restart the computer
When You Need Help with the RPC Error
The RPC Error is such a common error, it seems like it should be easy to fix. However, the DCOM Tunneling fix is only the beginning of troubleshooting an RPC server error. The good news is that you really don’t have to do anything when it comes to an RPC error if you maintain your computer with registry maintenance tools. Try researching the benefits of a registry cleaner to fix RPC errors.
On-the-Job Sprains and Strains
Most people consider workplace injuries a much larger threat in heavy industry or construction environments. While these occupations do often carry the risk of working around large machinery, dangerous tools, or abrasive chemicals, some of the most common occupational injuries can occur in almost any type of workplace. In fact, the United States Bureau of Labor Statistics determined that, in 2003, sprains and strains were the most common class of workplace injury. An employee can suffer a strain or sprain in almost any work environment, from a highrise construction site to a cubicle in a comfortable office building.
The statistics involving strains and sprains are startling. The aforementioned Bureau of Labor study found that they were responsible for 43% of the workplace injuries requiring employees to miss work in the private sector. They were the basis for 55% of WorkCover claims by employees seeking compensation. Combined, bruises, contusions, cuts, fractures, sprains and strains account for nearly two thirds of the injuries that caused employees to miss at least one day of work.
Most workplace sprains and strains occur due to “manual handling,” which is a blanket term used to describe tasks in which a person lifts, pulls, carries, pushes, or restrains any object. The number of job functions falling under the manual handling classification is almost endless: things like moving boxes, pulling levers, using a tool, and even working on a computer can all be included. With such a broad definition, it seems that almost all jobs can potentially involve a manual handling aspect, and in turn, can present a risk for occupational sprain and strain injuries. This is not far from the truth. Without active vigilance from employers, even seemingly harmless activities can put employees at risk for painful injuries that can cause them to miss work.
In order to avoid causing their employees to fall victim to sprains and strains, employers have a responsibility to provide workers with a work environment free of unnecessary risks. Employees should not be expected to lift loads that are too heavy for them or handle heavy objects in harmful or uncomfortable stances or postures. Workstations, including computer terminals, should be designed ergonomically, allowing for pain-free use over long periods of time. If an action or motion must be repeated by a worker, it should be regulated so that the frequency or timing does not put that individual at undue risk for sprain or strain injuries. If an employer does not fulfill these responsibilities and a worker is injured, a liability lawsuit may be a real possibility.
Windows Vista Boot Process Overview
The Windows Vista” boot process differs from Windows® XP in the way the operating system is located and initialized. Start-up begins with the BIOS loading the Master Boot Record (MBR) on the bootable disk. The MBR in turn loads the Partition Boot Record (PBR) on the active partition. So far, Windows Vista remains relatively unchanged.
Windows Vista is different from XP starting by the fact the PBR code written by Windows Vista no longer looks for Ntldr. The new boot loader in Windows Vista is Bootmgr. This component loads the Boot Configuration Database (BCD), which in turn loads an OS loader boot application (Winload.exe, in the case of Windows Vista). Finally, the OS loader application is responsible for initializing the kernel. This process is illustrated below.
You can think of this change in two elements:
1. The two key actions performed by Ntldr in previous Windows versions have been divided between two components:
2. Bootmgr reads the boot configuration, including device and path locations.
WindowsSystem32Winload.exe initializes the kernel.
The boot configuration stored by Boot.ini in previous Windows versions is now stored in an extensible database, BootBCD, the Boot Configuration Database (BCD).
These changes are significant because of the impact they have:
The boot process can be extended to support other applications, such as other operating systems or other versions of the OS.
Only nonversion-specific components are stored in the root of the active partition. This means that theoretically Windows Vista could be installed on a machine running some future Windows version with the same boot structure, and it would not break the boot process for that future version. With legacy Windows, installing an older Windows version last causes the newer version to fail on start-up. This is due to version-specific code improvements in Ntldr.
Tool-oriented boot entries can be supported to offer maintenance options on boot when a previous start-up failed. In the past, Windows supported an menu provided by a target operating system. This new structure can make tools available earlier during the boot process, meaning that they are available even if all OS-specific boot entries are damaged. The Windows Memory Diagnostic tool is provided in the boot menu in this way.
BCD Store
The Boot Configuration Data (BCD) store contains boot configuration parameters and controls how the operating system is started in Microsoft Windows Vista operating system. These parameters were previously in the Boot.ini file in BIOS-based operating systems or in the nonvolatile RAM (NVRAM) entries in Extensible Firmware Interface-based operating systems. You can use the Bcdedit.exe command line tool to affect the Windows code which runs in the pre-operating system environment by adding, deleting, editing, and appending entries in the BCD store. Bcdedit.exe is located in the WindowsSystem32 directory of the Windows Vista partition.
The BCD is a database used by Bootmgr. It contains the functions of Boot.ini and is located in the {ActivePartition}boot folder
Bcdedit.exe
You can use Bcdedit.exe to modify the Windows code which runs in the pre-operating system environment by adding, deleting, editing, and appending entries in the BCD store. Bcdedit.exe is located in the WindowsSystem32 directory of the Windows Vista partition.
Boot.ini Compared to BCD
BCD eliminates the need for Boot.ini in Windows Vista, although Boot.ini is still present on dual-boot systems for backwards compatibility. Because the BCD boots to the boot environment first instead of Ntldr, the location of Ntldr is not verified unless a legacy operating system is chosen.
Configuration Tools
The BCD store can be modified or repaired using several tools:
System Properties in Control Panel
SystemPropertiesAdvanced.exe
Msconfig
Windows Recovery Environment (WinRE) Startup Repair
Bcdedit.exe
Bootrec.exe
Most of these tools enable you to perform simple tasks, such as setting a boot menu timeout, setting a default operating system, or configuring boot options such as /SOS and /SAFEBOOT. Others are repair-oriented tools; Startup Repair and Bootrec.exe, in particular, provide automated mechanisms for fixing problems in the BCD.
Bcdedit.exe is the main tool for detailed BCD store modifications. You can use Bcdedit to change Bootmgr options; add boot, delete, and edit boot entries; import and export the BCD store; and create a new store if it becomes significantly damaged. Bcdedit.exe is located in the WindowsSystem32 directory of the Windows Vista partition and is also available in WinRE.
BCD Store Location
The BCD store is a registry hive, stored as BootBCD on the active partition. This hive is loaded but hidden from view in Regedit.exe within Windows Vista. The store is loaded to the following registry location: HKLMBCD00000000.
You can also view the store manually in WinRE by loading the hive from the Boot folder. To obtain a copy of the hive on a running system, use the Bcdedit /export filename command to export a hive file for offline examination. This command exports the BCD store to a file called filename in the current directory.
Related Components
Msconfig
Msconfig is the preferred PSS UI tool for managing boot settings. The tool supports BCD and allows the user to enumerate all BCD objects in the system store. It allows certain elements to be altered for each OS object, including debug settings, safe mode settings, and other popular PSS options. It cannot be used with the WinRE console; Bcdedit needs to be used in these cases.
Bcdedit.exe
Bcdedit.exe is a command line tool that can be used to manage BCD settings. In summary, Bcdedit.exe is a replacement for Bootcfg.exe. However, it is enhanced for better scripting and to expose some of the more powerful features of BCD that bootcfg.exe did not expose for manipulating Boot.ini. Bcdedit.exe is designed to work on previous operating systems and in recovery environments.
How to Install IIS on Windows XP SP2 Without the CD
Having problem installing a piece of software on your system is frustrating. Do you want to find out how to install IIS on Windows XP SP2 without actually having the SP2 CD?
The problem I experienced with while installing IIS:
I tried to install Internet Information Service (IIS) on my Windows XP Service Pack 2. The setup failed and kept asking for Windows XP SP2 CD. I only had Windows XP SP1 CD and the Service Pack 2 Service Pack 2 installation package.
I tried to find an existing solution on the Internet using Google. I read and attempted many solutions including a complicated one from Microsoft Support (support.microsoft.com/?kbid=894351) and some simple solutions “Installing IIS after Service Pack 2″. None of those solutions I found actually worked, or the instruction was too complicated to follow
Finally I had to solve by myself. Here is what I did: I had unpacked the SP2 installation file using WinRar a while ago and compiled a CD image file from it. I mounted this CD image onto a virtual CD. I install and use this Virtual CD to supply the missing files which are somewhere inside the I386 folder.
Here are the steps you can follow to install IIS without having a Windows XP SP2 CD:
Download the XP SP2 installation file (softwarepatch.com/windows/xpsp2.html) if you do not already have.
Extract the content of the file into a folder using WinRar (win-rar.com) or similar compression software;
Start installing IIS using standard procedure (Control Panel > Add and Remove Programs > Windows Components)
When it prompts for source folder, browse for the I386 folder that you extracted earlier
When it prompts for missing files, browse I386 and its sub-folders for them.
The solution was easier than it look. You do not need to riskily alter the Windows security folder. You do not need to spend time merging SP2 into Windows XP CD. All you need to do is to use what were already there.
Modern Forms of Communications
FAX (Facsimile Telegraphy) – Facsimile telegraphy deals with the transmission of typewritten or handwritten message , drawings , graphics , pictures or any matter which cannot be sent through telegraphs , telephones or teleprinters.This machine operates by converting the variances of light reflected from the image of the original matter into electrical impulses which can be reconverted onto the image from on reception . Connections can be made over very long distances using the public telephone networks or radio links. Fax is perhaps the speediest system presently available and transmitting and receiving a standard letter size document takes approximately four minutes, irrespective of the amount of matter on it. In this system there is no scope for copying errors and so high order skills required at high skills. Even typed matter can be transmitted more effectively through fax than through the teleprinter since the former completely does away with the element of checking for errors inadvertently incorporated during transmittal of the matter.
ELECTRONIC MAIL (E-Mail) – This , too is a progeny of computer technology. It facilities the transmittal of messages through the use of computer storage and computer inter-links , thus eliminating postal delays. The message is simply keyed into the system. The signals, converted into digital pulses are stored in the computer‘s memory for retrieval. The message can be retrieved at the recipient’s convenience. Thus apart from being time saving , electronic mail is a more convenient and unobtrusive method of sending a message as the sender can be sure of not disturbing the recipient. In close inhouse communication, links are established either by the CPU of computer network internet workstations. In distant communication between offices at different locations , an extensive network of microwave or satellite technology is used for the transmission of electronic mail. Usually group communication takes place in person , in the same room but the new technology provides a facility for discussion with the group of persons on the internet . You can conduct a meeting , hold a group discussion or brief people scattered across the country or around the world. You can consult a number of experts through computers using decision support systems for their views before making a decision or for finalizing a plan of action. In teleconferencing , the attention is focused on the idea or concept that is being communicated. This is an advantage of the method but sometimes this overemphasis on the message with a corresponding neglect of the person communicating it, may not be fully in tune with the corporate culture , which needs dynamic medium of communication.
Teleconferencing – Usually, group communication takes place in person, in the same room, but new technology provides a facility for discussion with a group of persons on the internet. You can conduct a meeting,hold a group discussion or brief people scattered across the country or around the World. You can consult a number of experts through computers using group decision support systems for their views before making a decision or for finalising a plan of action. In teleconferencing , the attention is focused on the idea or concept that is being communicated. This is the advantage of the method but sometimes this overemphasis on the message with a corresponding neglect of the person communicating it,may not fully in tune with the corporate culture,which needs a dynamic medium of communication.
It is an arrangement which facilitates the speakers to communicate each other in different localities using public telephone links. Participants of the conference located in different geographical distance areas can discuss issues by using their terminals that are linked together viz the telecommunication network.
In recent years, big business organizations are using teleconferencing method to conduct business meetings with the concerned executives who are geographically scattered all over a region. For instance, a firm having a chain of branch offices offers a network for teleconferencing service. The members or participants can go their local branch and participate,and interact in discussion with the speaker at other branches. It may be mentioned that an alternative of computer conferencing is teleconferencing. An electronic linkage of geographically scattered people is no doubt an oral communication through a medium but without the presence of persons. The advantage of face to face conversion cannot be obtained from teleconferencing which cannot replace them. Body movements , facial expressions which also communicate feelings,attitudes etc. cannot be seen with teleconferencing perfectly. But on the other hand, teleconferencing offers a number of advantages like :
1. Time is saved.
2. Cost and energy are saved.
3. Travel to distance place to attend conference is avoided.
4. No monotony or fatigue.
5. The work arrangements , facilities, and accommodation is eliminated.
Causes and Treatment of Right Shoulder Pain
Pain in the right shoulder could be from several factors. If you have right shoulder pain, seek out your primary care provider for a diagnosis, and treatment options. Indications of right shoulder pain vary in relation to the exact spot where the injury or disease occurred.
Three joints and three bones make up the shoulder region: the humerus (upper arm), collarbone and scapula (shoulder blade). A group of muscles and related tendons called the rotator cuff, attach to the shoulder joint. In addition to the ligaments, tendons and muscles that surround the shoulder joint and bones, there are small fluid-filled sacs that give people smooth muscle movement. These sacs are called bursa.
Shoulder pain can be caused by any of these structures. Trauma, overuse, or infection can cause inflammation of the bursa or bursitis. A painful inflammation of the joints, widely known as arthritis, can be caused by osteoarthritis (depreciation). Arthritis can also be caused by a reaction from the body’s immune system that results in inflammation. Strains or sprains to the muscles and tendons around the rotator cuff are the cause of rotator cuff syndrome. A tear in the tendons can also be the cause of rotator cuff syndrome. An intense pain in the shoulder can also be caused by a break or dislocation.
Specifically to the right shoulder, there may be other reasons which are not linked to the shoulder itself could give rise pain to the right shoulder. Cited pain, or pain giving symptoms in different body region or organ, could come out as pain in the right shoulder part.An heated gallbladder or gallstones penetrating the canals could cause pain under the right shoulder blade. Liver disease or duodenal (small intestine) ulcer may also leads right shoulder pain.
If you get shoulder pain, you ought to look for assistance from a medical professional if home care remedies do not relieve the pain, if you have sustained an injury or if you have intense pain. To commence the assessment of the problem, a physical examination will be done.
The range of movement of arm and shoulder must be checked to find out if any certain position or motion causes any pain or to see if the shoulder is not able to move. The shoulder will be examined for areas of weakness, tenderness, deformity, or muscle wasting. Depending on physical exam determinations, more testing might be conducted.
A variety of diagnostic tests may be performed to assess the damage to the shoulder. X-rays can show fractures, breaks and other abnormalities of the bones in the shoulder. Imagining tests such as an MRI (magnetic resonance imaging) or CT (computerized tomography) scan allow doctors to see the soft tissues of the shoulder joint, as well as the bones. Nerve damage may be found through an electromyogram (EMG) test. Sometimes right shoulder pain is the result of referred pain. Doctors will check out other body systems as well.
After you have found the reason for your shoulder pain, you and your medical professional can discuss the appropriate treatment options. Pain that involved the shoulder itself will be addressed directly. Most often you will find that you can treat your shoulder pain with non-invasive treatment methods.
Non-surgical treatment comprises of rest from exasperating activities or use of a sling to sustain the shoulder; easy exercise or physiotherapy to improve muscle strength and flexibility; medications such as ibuprofen or acetaminophen, to alleviate inflammation and pain; or even a corticosteroid injection into the painful region to lessen inflammation.
Surgery may be required to treat some conditions that manifest themselves through shoulder pain. Arthroscopic surgery is one type of procedure that is commonly used. This type of surgery uses very small incisions and tiny instruments to diagnose problems that may not be picked up through routine testing. There are other situations, however, in which conventional open surgery may be needed to end shoulder pain.
Using The Posture Bra As A Back Support
Sometimes, it things can just get desperate. Tired of neck and upper back pain, women seek out posture bra back support. Here’s where things can get tricky for women versus men. While both men and women have the constant force of gravity pulling on them, women have a little something extra in the front that can more adversely affect them.
For most people, it’s the position of the head that keeps gravity pulling all day on their necks and upper backs. Move your head forward an inch and you have increased the force of gravity on your supporting muscles by a factor of ten.
The answer? Work on improving the neck and back muscle strength to gradually bring the head back over the shoulders and eliminate the head moving forward and increasing the pressure on your spine and muscles.
For women, they also deal with their chests being acted upon by gravity, pulling them downward. Be warned, though. Adding a back support of any kind will help support your back but not fix your posture issue. If you seek out a posture bra back support, you’ll want to take a two-tier approach to ending your back pains.
You’ll still want to find an exercise program to build up the strength in your neck and back muscles, which will almost immediately get you some back pain relief. If you proceed with the posture bra purchase, you’ll just want to make sure that you don’t lazy about taking care of your postural muscles.
Wearing a posture support of any kind for extended periods of time (like weeks or months) can gradually decrease the strength of your muscles. It’s like they’re not even being used, so why would they stay strong? If you stopped using your legs, they too would eventually get weaker. The same principle applies to your back muscles.
Evaluate your computer workstation and take a look at any current exercises you’re doing. Do your normal daily activities use your back muscles? Or can you add in things that increase your need for your postural muscles, which will reduce your need to seek out a posture bra back support. Sometimes we think we’re doing all we can to solve a problem, but our efforts just are specific enough to truly address the problem.
Intranet
Introduction to Intranets
What exactly is an intranet? It’s one of those terms that’s more thrown around than understood, and has become more of a buzzword than a commonly understood idea. Simply put, an intranet is a private network with Internet technology used as the underlying architecture. An intranet is built using the Internet’s TCP/IP protocols for communications. TCP/IP protocols can be run on many hardware platforms and cabling schemes. The underlying hardware is not what makes an intranet-it’s the software protocols that matter.
Intranets can co-exist with other local area networking technology. In many companies, existing “legacy systems” including mainframes, Novell networks, minicomputers, and various databases, are being integrated into an intranet. A wide variety of tools allow this to happen. Common Gateway Interface (CGI) scripting is often used to access legacy databases from an intranet. The Java programming language can be used to access legacy databases as well.
With the enormous growth of the Internet, an increasing number of people in corporations use the Internet for communicating with the outside world, for gathering information, and for doing business. It didn’t take long for people to recognize that the components that worked so well on the Internet could be equally valuable internally and that is why intranets are becoming so popular. Some corporations do not have TCP/IP networks, the protocol required to access the resources of the Internet. Creating an intranet in which all the information and resources can be used seamlessly has many benefits. TCP/IP-based networks make it easy for people to access the network remotely, such as from home or while traveling. Dialing into an intranet in this way is much like connecting to the Internet, except that you’re connecting to a private network instead of to a public Internet provider. Interoperability between networks is another substantial bonus.
Security systems separate an intranet from the Internet. A company’s intranet is protected by firewalls-hardware and software combinations that allow only certain people to access the intranet for specific purposes.
Intranets can be used for anything that existing networks are used for-and more. The ease of publishing information on the World Wide Web has made them popular places for posting corporate information such as company news or company procedures. Corporate databases with easy-to-build front-ends use the Web and programming languages such as Java.
Intranets allow people to work together more easily and more effectively. Software known as groupware is another important part of intranets. It allows people to collaborate on projects; to share information; to do videoconferencing; and to establish secure procedures for production work. Free server and client software and the multitude of services, like newsgroups, stimulated the Internet’s growth. The consequence of that growth stimulated and fueled the growth of intranets. The ease with which information can be shared, and with which people can communicate with one another will continue to drive the building of intranets.
A Global View of an Intranet
An intranet is a private corporate or educational network that uses the Internet’s TCP/IP protocols for its underlying transport. The protocols can run on a variety of network hardware, and can also co-exist with other network protocols, such as IPX. People from inside an intranet can get at the larger Internet resources, but those on the Internet cannot get into the intranet, which allows only restricted access from the Internet.
Videoconferencing is an important application that requires sending massive quantities of data. Intranets can be built using components that allow the extremely high bandwidths required for transferring such information.
Often an intranet is composed of a number of different networks inside a corporation that all communicate with one another via TCP/IP. These separate networks are often referred to as subnets.
Software that allows people to communicate with each other via e-mail and public message boards and to collaborate on work using workgroup software is among the most powerful intranet programs. Applications that allow different corporate departments to post information, and for people to fill out corporate forms, such as time sheets, and for tapping into corporate financial information are very popular.
Much of the software used on intranets is standard, off-the-shelf Internet software such as the Netscape Navigator and the Microsoft Explorer Web browsers. And customized programs are often built, using the Java programming language and CGI scripting.
Intranets can also be used to allow companies to do business-to-business transactions, such as ordering parts, sending invoices, and making payments. For extra security, these intranet-to-intranet transactions need never go out over the public Internet, but can travel over private leased lines instead.
Intranets are a powerful system for allowing a company to do business online, for example, to allow anyone on the Internet to order products. When someone orders a product on the Internet, information is sent in a secure manner from the public Internet to the company’s intranet, where the order is processed and completed.
In order to protect sensitive corporate information, and to ensure that hackers don’t damage computer systems and data, security barriers called firewalls protect an intranet from the Internet. Firewall technology uses a combination of routers, servers and other hardware and software to allow people on an intranet to use Internet resources, but blocks outsiders from getting into the intranet.
Many intranets have to connect to “legacy systems”-hardware and databases that were built before an intranet was constructed. Legacy systems often use older technology not based on the intranet’s TPC/IP protocols. There are a variety of ways in which intranets can tie to legacy systems. A common way is to use CGI scripts to access the database information and pour that data into HTML formatted text, making it available to a Web browser.
Information sent across an intranet is sent to the proper destination by routers, which examine each TCP/IP packet for the IP address and determine the packet’s destination. It then sends the packet to the next router closest to the destination. If the packet is to be delivered to an address on the same subnetwork of the intranet it was sent from, the packet may be able to be delivered directly without having to go through any other routers. If it is to be sent to another subnetwork on the intranet, it will be sent to another internal router address. If the packet is to be sent to a destination outside the intranet-in other words, to an Internet destination-the packet is sent to a router that connects to the Internet
How TCP/IP and IPX Work on Intranets
What distinguishes an intranet from any other kind of private network is that it is based on TCP/IP-the same protocols that apply to the Internet. TCP/IP refers to two protocols that work together to deliver data: the Transmission Control Protocol (TCP) and the Internet Protocol (IP). When you send information across an intranet, the data is broken into small packets. The packets are sent independently through a series of switches called routers. Once all the packets arrive at their destination, they are recombined into their original form. The Transmission Control Protocol breaks the data into packets and recombines them on the receiving end. The Internet Protocol handles the routing of the data and makes sure it gets sent to the proper destination.
In some companies, there may be a mix of TCP/IP-based intranets and networks based on other networking technology, such as NetWare. In that instance, the TCP/IP technology of an intranet can be used to send data between NetWare or other networks, using a technique called IP tunneling. In this instance, we’ll look at data being sent from one NetWare network to another, via an intranet. NetWare networks use the IPX (Internet Packet Exchange) protocol as a way to deliver data-and TCP/IP networks can’t recognize that protocol. To get around this, when an IPX packet is to be sent across an intranet, it is first encapsulated inside an IP packet by a NetWare server specifically for and dedicated to providing the IP transport mechanism for IPX packets.
Data sent within an intranet must be broken up into packets of less than 1,500 characters each. TCP breaks the data into packets. As it creates each packet, it calculates and adds a checksum to the packet. The checksum is based on the byte values, that is, the precise amount of data in the packet.
Each packet, along with the checksum, is put into separate IP wrappers or “envelopes.” These wrappers contain information that details exactly where on the intranet-or the Internet-the data is to be sent. All of the wrappers for a given piece of data have the same addressing information so that they can all be sent to the same location for reassembly.
The packets travel between networks by intranet routers. Routers examine all IP wrappers and look at their addresses. These routers determine the most efficient path for sending each packet to its final destination. Since the traffic load on an intranet often changes, the packets may be sent along different routes, and the packets may arrive out of order. If the router sees the address is one located inside the intranet, the packet may be sent directly to its destination, or it may instead be sent to another router. If the address is located out on the Internet, it will be sent to another router so it can be sent across the Internet.
As the packets arrive at their destination, TCP calculates a checksum for each packet. It then compares this checksum with the checksum that has been sent in the packet. If the checksums don’t match, TCP knows that the data in the packet has been corrupted during transmission. It then discards the packet and asks that the original packet be retransmitted.
TCP includes the ability to check packets and to determine that all the packets have been received. When all the non-corrupt packets are received, TCP assembles them into their original, unified form. The header information of the packets relays the sequence of how to reassemble the packets.
An intranet treats the IP packet as it would any other, and routes the packet to the receiving NetWare network. On the receiving NetWare network, a NetWare TCP/IP server decapsulates the IP packet-it discards the IP packet, and reads the original IPX packet. It can now use the IPX protocol to deliver the data to the proper destination.
How the OSI Model Works
A group called the International Standards Organization (ISO) has put together the Open Systems Interconnect (OSI) Reference Model, which is a model that describes seven layers of protocols for computer communications. These layers don’t know or care what is on adjacent layers. Each layer, essentially, only sees the reciprocal layer on the other side. The sending application layer sees and talks to the application layer on the destination side. That conversation takes place irrespective of, for example, what structure exists at the physical layer, such as Ethernet or Token Ring. TCP combines the OSI model’s application, presentation, and session layers into one which is also called the application layer.
The application layer refers to application interfaces, not programs like word processing. MHS (Message Handling Service) is such an interface and it operates at this level of the OSI model. Again, this segmentation and interface approach means that a variety of email programs can be used on an intranet so long as they conform to the MHS standard at this application interface level.
The presentation layer typically simply provides a standard interface between the application layer and the network layers. This type of segmentation allows for the great flexibility of the OSI model since applications can vary endlessly, but, as long as the results conform to this standard interface, the applications need not be concerned with any of the other layers.
The session layer allows for the communication between sender and destination. These conversations avoid confusion by speaking in turn. A token is passed to control and to indicate which side is allowed to speak. This layer executes transactions, like saving a file. If something prevents it from completing the save, the session layer, which has a record of the original state, returns to the original state rather than allowing a corrupt or incomplete transaction to occur.
The transport layer segments the data into acceptable packet sizes and is responsible for data integrity of packet segments. There are several levels of service that can be implemented at this layer, including segmenting and reassembly, error recovery, flow control, and others.
The IP wrapper is put around the packet at the network or Internet layer. The header includes the source and destination addresses, the sequence order, and other data necessary for correct routing and rebuilding at the destination.
The data-link layer frames the packets-for example, for use with the PPP (Point to Point). It also includes the logical link portion of the MAC sublayer of the IEEE 802.2, 802.3 and other standards.
Ethernet and Token Ring are the two most common physical layer protocols. They function at the MAC (Media Access Control) level and move the data over the cables based on the physical address on each NIC (Network Interface Card). The physical layer includes the physical components of the IEEE 802.3 and other specifications.
How TCP/IP Packets Are Processed
Protocols such as TCP/IP determine how computers communicate with each other over networks such as the Internet. These protocols work in concert with each other, and are layered on top of one another in what is commonly referred to as a protocol stack. Each layer of the protocol is designed to accomplish a specific purpose on both the sending and receiving computers. The TCP stack combines the application, presentation, and the session layers into a single layer also called the application layer. Other than that change, it follows the OSI model. The illustration below shows the wrapping process that occurs to transmit data.
The TCP application layer formats the data being sent so that the layer below it, the transport layer, can send the data. The TCP application layer performs the equivalent actions that the top three layers of OSI perform: the application, presentation, and session layers.
The next layer down is the transport layer, which is responsible for transferring the data, and ensures that the data sent and the data received are in fact the same data-in other words, that there have been no errors introduced during the sending of the data. TCP divides the data it gets from the application layer into segments. It attaches a header to each segment. The header contains information that will be used on the receiving end to ensure that the data hasn’t been altered en route, and that the segments can be properly recombined into their original form.
The third layer prepares the data for delivery by putting them into IP datagrams, and determining the proper Internet address for those datagrams. The IP protocol works in the Internet layer, also called the network layer. It puts an IP wrapper with a header onto each segment. The IP header includes information such as the IP address of the sending and receiving computers, and the length of the datagram, and the sequence order of the datagram. The sequence order is added because the datagram could conceivably exceed the size allowed for network packets, and so would need to be broken into smaller packets. Including the sequence order will allow them to be recombined properly.
The Internet layer checks the IP header and checks to see whether the packet is a fragment. If it is, it puts together fragments back into the original datagram. It strips off the IP header, and then sends the datagram to the transport layer.
The transport layer looks at the remaining header to decide which application layer protocol-TCP or UDP-should get the data. Then the proper protocol strips off the header and sends the data to the receiving application.
The application layer gets the data and performs, in this case, an HTTP request.
The next layer down, the data link layer, uses protocols such as the Point-to-Point Protocol (PPP) to put the IP datagram into a frame. This is done by putting a header-the third header, after the TCP header and the IP header-and a footer around the IP datagram to fra-me it. Included in the frame header is a CRC check that checks for errors in the data as the data travels over the network.
The data-link layer ensures that the CRC for the frame is right, and that the data hasn’t been altered while it was sent. It strips off the frame header and the CRC, and sends the frame to the Internet layer.
On the receiving computer, the packet travels through the stack, but in the opposite order from which the packet was created. In other words, it starts at the bottom layer, and moves its way up through the protocol stack. As it moves up, each layer strips off the header information that was added by the TCP/IP stack of the sending computer.
The final layer is the physical network layer, which specifies the physical characteristics of the network being used to send data. It describes the actual hardware standards, such as the Ethernet specification. The layer receives the frames from the data link layer, and translates the IP addresses there into the hardware addresses required for the specific network being used. Finally, the layer sends the frame over the network.
The physical network layer receives the packet. It translates the hardware address of the sender and receiver into IP addresses. Then it sends the frame up to the data link layer.
How Bridges Work
Bridges are hardware and software combinations that connect different parts of a single network, such as different sections of an intranet. They connect local area networks (LANs) to each other. They are generally not used, however, for connecting entire networks to each other, for example, for connecting an intranet to the Internet, or an intranet to an intranet, or to connect an entire subnetwork to an entire subnetwork. To do that, more sophisticated pieces of technology called routers are used.
When there is a great amount of traffic on an Ethernet local area network, packets can collide with one another, reducing the efficiency of the network, and slowing down network traffic. Packets can collide because so much of the traffic is routed among all the workstations on the network.
In order to cut down on the collision rate, a single LAN can be subdivided into two or more LANs. For example, a single LAN can be subdivided into several departmental LANs. Most of the traffic in each departmental LAN stays within the department LAN, and so it needn’t travel through all the workstations on all the LANs on the network. In this way, collisions are reduced. Bridges are used to link the LANs. The only traffic that needs to travel across bridges is traffic bound for another LAN. Any traffic within the LAN need not travel across a bridge.
Each packet of data on an intranet has more information in it than just the IP information. It also includes addressing information required for other underlying network architecture, such as for an Ethernet network. Bridges look at this outer network addressing information and deliver the packet to the proper address on a LAN
Bridges consult a learning table that has the addresses of all the network nodes in it. If a bridge finds that a packet belongs on its own LAN, it keeps the packet inside the LAN. If it finds that the workstation is on another LAN, it forwards the packet. The bridge constantly updates the learning table as it monitors and routes traffic.
Bridges can connect LANs in a variety of different ways. They can connect LANs using serial connections over traditional phone lines and modems, over ISDN lines, and over direct cable connections. CSU/DSU units are used to connect bridges to telephone lines for remote connectivity.
Bridges and routers are sometimes combined into a single product called a brouter. A brouter handles both bridging and routing tasks. If the data needs to be sent only to another LAN on the network or subnetwork, it will act only as a bridge delivering the data based on the Ethernet address. If the destination is another network entirely, it will act as a router, examining the IP packets and routing the data based on the IP address.
How Intranet Routers Work
Just as routers direct traffic on the Internet, sending information to its proper destination, and routers on an intranet perform the same function. Routers-equipment that is a combination of hardware and software-can send the data to a computer on the same sub network inside the intranet, to another network on the intranet, or outside to the Internet. They do this by examining header information in IP packets, and then sending the data on its way. Typically, a router will send the packet to the next router closest to the final destination, which in turn sends it to an even closer router, and so on, until the data reaches its intended recipient.
A router has input ports for receiving IP packets, and output ports for sending those packets toward their destination. When a packet comes to the input port, the router examines the packet header, and checks the destination in it against a routing table-a database that tells the router how to send packets to various destinations.
Based on the information in the routing table, the packet is sent to a particular output port, which sends the packet to the next closest router to the packet’s destination.
If packets come to the input port more quickly than the router can process them, they are sent to a holding area called an input queue. The router then processes packets from the queue in the order they were received. If the number of packets received exceeds the capacity of the queue (called the length of the queue), packets may be lost. When this happens, the TCP protocol on the sending and receiving computers will have the packets re-sent.
In a simple intranet that is a single, completely self-contained network, and in which there are no connections to any other network or the intranet, only minimal routing need be done, and so the routing table in the router is exceedingly simple with very few entries, and is constructed automatically by a program called ifconfig.
In a slightly more complicated intranet which is composed of a number of TCP/IP-based networks, and connects to a limited number of TCP/IP-based networks, static routing will be required. In static routing, the routing table has specific ways of routing data to other networks. Only those pathways can be used. Intranet administrators can add routes to the routing table. Static routing is more flexible than minimal routing, but it can’t change routes as network traffic changes, and so isn’t suitable for many intranets.
In more complex intranets, dynamic routing will be required. Dynamic routing is used to permit multiple routes for a packet to reach its final destination. Dynamic routing also allows routers to change the way they route information based on the amount of network traffic on some paths and routers. In dynamic routing, the routing table is called a dynamic routing table and changes as network conditions change. The tables are built dynamically by routing protocols, and so constantly change according to network traffic and conditions.
There are two broad types of routing protocols: interior and exterior. Interior routing protocols are typically used on internal routers inside an intranet that routes traffic bound only for inside the intranet. A common interior routing protocol is the Routing Information Protocol (RIP). Exterior protocols are typically used for external routers on the Internet. AÊcommon exterior protocol is the Exterior Gateway Protocol (EGP).
Intranets come in different sizes. In a small company, an intranet can be composed of only a handful of computers. In a medium-sized business, it may include dozens or hundreds of computers. And in a large corporation, there may be thousands of computers spread across the globe, all connected to a single intranet. When intranets get large, they need to be subdivided into individual subnets or subnetworks.
To understand how subnetting works, you first need to understand IP addresses. Every IP address is a 32-bit numeric address that uniquely identifies a network and then a specific host on that network. The IP address is divided into two sections: the network section, called the netid, and the host section, called the hostid.
Each 32-bit IP address is handled differently, according to what class of network the address refers to. There are three main classes of network addresses: Class A, Class B, and Class C. In some classes, more of the 32-bit address space is devoted to the netid, while in others, more of the address space is devoted to the hostid. In a Class A network, the netid is composed of 8 bits, while the hostid is composed of 24 bits. In a Class B network, both the netid and the hostid are composed of 16 bits. In a Class C network, the netid is composed of 24 bits, while the hostid is composed of 8 bits. There’s a simple way of knowing what class a network is in. If the first number of the IP address is less than 128, the network is a Class A address. If the first number is from 128 to 191, it’s a Class B network. If the first number is from 192 to 223, it’s a Class C network. Numbers above 223 are reserved for other purposes. The smaller the netid, the fewer number of networks that can be subnetted, but the larger number of hosts on the network. A Class A rating is best for large networks while a Class C is best for small ones.
To create a subnet, the demarcation line on the IP address is moved between the netid and the hostid, to give the netid more bits to work with and to take away bits from the hostid. To do this, a special number called a subnet mask is used.
Subnetting is used when intranets grow over a certain size and they begin to have problems. One problem is management of host IP addresses-making sure that every computer on the network has a proper, up-to-date host address, and that old host addresses are put out of use until needed in the future. In a corporation spread out over several locations-or across the world-it’s difficult, if not impossible, to have one person responsible for managing the host addresses at every location and department in the company.
Another problem has to do with a variety of hardware limitations of networks. Dissimilar networks may all be part of an intranet. An intranet may have some sections that are Ethernet, other sections that are Token Ring networks, and conceivably other sections that use different networking technologies altogether. There is no easy way for an intranet router to link these dissimilar networks together and route the information to the proper places.
Another set of problems has to do with the physical limitations of network technology. In some kinds of networks, there are some strict limitations on how far cables can extend in the network. In other words, you can’t go over a certain distance of cabling without using repeaters or routers. A “thick” Ethernet cable, for example, can only be extended to 500 meters, while a “thin” Ethernet cable can only go to 300 meters. Routers can be used to link these cables together, so that an intranet can be extended well beyond those distances. But when that is done, each length of wire is essentially considered its own subnetwork.
Yet one more set of problems has to do with the volume of traffic that travels across an intranet. Often in a corporation, in a given department, most of the traffic is intradepartmental traffic-in other words, mail and other data that people within a department send to each another. The volume of traffic outside to other departments is considerably less. What’s called for is a way to confine intradepartmental traffic inside the departments, to cut down on the amount of data that needs to be routed and managed across the entire intranet.
Subnetting solves all these problems and more. When an intranet is divided into subnets, one central administrator doesn’t have to manage every aspect of the entire intranet. Instead, each subnet can take care of its own administration. That means smaller organizations within the larger organization can take care of problems such as address management and a variety of troubleshooting chores. If an intranet is subnetted by divisions or departments, it means that each division or department can guide the development of its own network, while adhering to general intranet architecture. Doing this allows departments or divisions more freedom to use technology to pursue their business goals.
Subnets also get around problems that arise when an intranet has within it different kinds of network architecture, such as Ethernet and Token Ring technologies. Normally-if there is no subnetting-a router can’t link these different networks together because they don’t have their own addresses. However, if each of the different networks is its own subnet-and so has its own network address-routers can then link them together and properly route intranet traffic.
Subnetting can also cut down on the traffic traveling across the intranet and its routers. Since much network traffic may be confined within departments, having each department be its own subnet means that all that traffic need never cross an intranet router and cross the intranet-it will stay within its own subnet.
Subnetting can also increase the security on an intranet. If the payroll department, for example, were on its own subnet, then much of its traffic would not have to travel across an intranet. Having its data traveling across the intranet could mean that someone could conceivably hack into the data to read it. Confining the data to its own subnet makes that much less likely to happen.
Dividing an intranet into subnets can also make the entire intranet more stable. If an intranet is divided in this way, then if one subnet goes down or is often unstable, it won’t affect the rest of the intranet.
This all may sound rather confusing. To see how it’s done, let’s take a look at a network, and see how to use the IP address to create subnets. Let’s say we have a Class B network. That network is assigned the address of 130.97.0.0. When a network is given an address, it is assigned the netid numbers-in this case, the 130.97-and it can assign the host numbers (in this case, 0.0) in any way that it chooses.
The 130.97.0.0 network is a single intranet. It’s getting too large to manage, though, and we’ve decided to divide it into two subnets. What we do is fairly straightforward. We take a number from the hostid field and use it to identify each of the subnets. So one subnet gets the address 130.97.1.0, and the other gets the address 130.97.2.0. Individual machines on the first subnet get addresses of 130.97.1.1, 130.97.1.2, and so on. Individual machines on the second subnet get addresses of 130.97.2.1, 130.97.2.2 and so on.
Sounds simple. But we have a problem. The Internet doesn’t recognize 130.97.1.0 and 130.97.2.0 as separate networks. It treats them both as 130.97.0.0 since the “1″ and “2″ that we’re using as a netid is only known to the Internet as a hostid. So our intranet router will not be able to route incoming traffic to the proper network.
To solve the problem, a subnet mask is used. A subnet mask is a 32-bit number in IP form used by intranet routers and hosts that will help routers understand how to route information to the proper subnet. To the outside Internet, there is still only one network, but the subnet mask allows routers inside the intranet to send traffic to the proper host.
A subnet mask is a number such as 255.255.255.0 (the built-in default for Class C addresses; the Class B default is 255.255.0.0 and the default for Class A is 255.0.0.0). A router takes the subnet mask and applies that number against the IP number of incoming mail to the network by using it to perform a calculation. Based on the resulting IP number, it will route mail to the proper subnet, and then to a particular computer on the subnet. For consistency, everyone in a particular intranet will use the same subnet mask.
Subnetting an Intranet
When intranets are over a certain size, or are spread over several geographical locations, it becomes difficult to manage them as a single network. To solve the problem, the single intranet can be subdivided into several subnets, subsections of an intranet that make them easier to manage. To the outside world, the intranet still looks as if it’s a single network.
If you’re building an intranet and want it to be connected to the Internet, you’ll need a unique IP address for your intranet network, which the InterNIC Registration Services will handle. There are three classes of intranet you can have: Class A, Class B, or Class C. Generally, a Class A rating is best for the largest networks, while a Class C is best for the smallest. A Class A network can be composed of 127 networks, and a total of 16,777,214 nodes on the network. A Class B network can be composed of 16,383 networks, and a total of 65,534 nodes. A Class C network can be composed of 2,097,151 networks, and 254 nodes.
When an intranet is assigned an address, it is assigned the first two IP numbers of the Internet numeric address (called the netid field) and the remaining two numbers (called the hostid field) are left blank, so that the intranet itself can assign them, such as 147.106.0.0. The hostid field consists of a number for a subnet and a host number.
When an intranet is connected to the Internet, a router handles the job of sending packets into the intranet from the Internet. In our example, all incoming mail and data comes to a router for a network with the netid of 147.106.0.0.
When intranets grow-for example, if there is a department located in another building, city, or country-there needs to be some way to manage network traffic. It may be impractical and physically impossible to route all the data necessary among many different computers spread across a building or the world. A second network-called a subnetwork or subnet-needs to be created.
In order to have a router handle all incoming traffic for a subnetted intranet, the first byte of the hostid field is used. The bits that are used to distinguish among subnets are called subnet numbers. In our example, there are two subnets on the intranet. To the outside world, there appears to be only one network.
Each computer on each subnet gets its own IP address, as in a normal intranet. The combination of the netid field, the subnet number, and then finally a host number, forms the IP address.
The router must be informed that the hostid field in subnets must be treated differently than non-subnetted hostid fields, otherwise it won’t be able to properly route data. In order to do this, a subnet mask is used. A subnet mask is a 32-bit number such as 255.255.0.0 that is used in concert with the numbers in the hostid field. When a calculation is performed using the subnet mask and the IP address, the router knows where to route the mail. The subnet mask is put in people’s network configuration files.
Overview of an Intranet Security System
Any intranet is vulnerable to attack by people intent on destruction or on stealing corporate data. The open nature of the Internet and TCP/IP protocols expose a corporation to attack. Intranets require a variety of security measures, including hardware and software combinations that provide control of traffic; encryption and passwords to validate users; and software tools to prevent and cure viruses, block objectionable sites, and monitor traffic.
The generic term for a line of defense against intruders is a firewall. A firewall is a hardware/software combination that controls the type of services allowed to or from the intranet.
Proxy servers are another common tool used in building a firewall. A proxy server allows system administrators to track all traffic coming in and out of an intranet.
A bastion server firewall is configured to withstand and prevent unauthorized access or services. It is typically segmented from the rest of the intranet in its own subnet or perimeter network. In this way, if the server is broken into, the rest of the intranet won’t be compromised.
Server-based virus-checking software can check every file coming into the intranet to make sure that it’s virus-free.
Authentication systems are an important part of any intranet security scheme. Authentication systems are used to ensure that anyone trying to log into the intranet or any of its resources is the person they claim to be. Authentication systems typically use user names, passwords, and encryption systems.
Server-based site-blocking software can bar people on an intranet from getting objectionable material. Monitoring software tracks where people have gone and what services they have used, such as HTTP for Web access.
One way of ensuring that the wrong people or erroneous data can’t get into the intranet is to use a filtering router. This is a special kind of router that examines the IP address and header information in every packet coming into the network, and allows in only those packets that have addresses or other data, like e-mail, that the system administrator has decided should be allowed into the intranet.
All intranets are vulnerable to attack. Their underlying TCP/IP architecture is identical to that of the Internet. Since the Internet was built for maximum openness and communication, there are countless techniques that can be used to attack intranets. Attacks can involve the theft of vital company information and even cash. Attacks can destroy or deny a company’s computing resources and services. Attackers can break in or pose as a company employee to use the company’s intranet resources.
Firewalls are hardware and software combinations that block intruders from access to an intranet while still allowing people on the intranet to access the resources of the Internet. Depending on how secure a site needs to be, and on how much time, money, and resources can be spent on a firewall, there are many kinds that can be built. Most of them, though, are built using only a few elements. Servers and routers are the primary components of firewalls.
Most firewalls use some kind of packet filtering. In packet filtering, a screening router or filtering router looks at every packet of data traveling between an intranet and the Internet.
Proxy servers on an intranet are used when someone from the intranet wants to access a server on the Internet. A request from the user’s computer is sent to the proxy server instead of directly to the Internet. The proxy server contacts the server on the Internet, receives the information from the Internet, and then sends the information to the requester on the intranet. By acting as a go-between like this, proxy servers can filter traffic and maintain security as well as log all traffic between the Internet and the network.
Bastion hosts are heavily fortified servers that handle all incoming requests from the Internet, such as FTP requests. A single bastion host handling incoming requests makes it easier to maintain security and track attacks. In the event of a break in, only that single host has been compromised, instead of the entire network. In some firewalls, multiple bastion hosts can be used, one for each different kind of intranet service request.
How Firewalls Work
Firewalls protect intranets from any attacks launched against them from the Internet. They are designed to protect an intranet from unauthorized access to corporate information, and damaging or denying computer resources and services. They are also designed to stop people on the intranet from accessing Internet services that can be dangerous, such as FTP.
Intranet computers are allowed access to the Internet only after passing through a firewall. Requests have to pass through an internal screening router, also called an internal filtering routeror choke router. This router prevents packet traffic from being sniffed remotely. A choke router examines all pack-ets for information such as the source and destination of the packet.
The router compares the information it finds to rules in a filtering table, and passes or drops the packets based on those rules. For example, some services, such as rlogin, may not be allowed to run. The router also might not allow any packets to be sent to specific suspicious Internet locations. A router can also block every packet traveling between the Internet and the internal network, except for e-mail. System administrators set the rules for determining which packets to allow in and which to block.
When an intranet is protected by a firewall, the usual internal intranet services are available-such as e-mail, access to corporate databases and Web services, and the use of groupware.
Screened subnet firewalls have one more way to protect the intranet-an exterior screening router, also called an exterior filtering router or an access router. This router screens packets between the Internet and the perimeter network using the same kind of technology that the interior screening router uses. It can screen packets based on the same rules that apply to the internal screening router and can protect the network even if the internal router fails. It also, however, may have additional rules for screening packets specifically designed to protect the bastion host.
As a way to further protect an intranet from attack, the bastion host is placed in a perimeter network-a subnet-inside the firewall. If the bastion host was on the intranet instead of a perimeter network and was broken into, the intruder could gain access to the intranet.
A bastion host is the main point of contact for connections coming in from the Internet for all services such as e-mail, FTP access, and any other data and requests. The bastion host services all those requests-people on the intranet contact only this one server, and they don’t directly contact any other intranet servers. In this way, intranet servers are protected from attack.
How to Make Computer Music With VST Plugins and VSTi Instruments
VST plugins are beginning to gather a lot more interest as music buffs/computer buffs put these two interests together. What was once thought impossible by many astute computer operators is now beginning to appear as not being all that difficult.
VST plugins in its simple terminology means Virtual Studio Technology by Steinberg. Imagine being able to have your very own virtual studio. The VST is actually the interface that allows the use of software consisting of action synthesizers and effects the plugins with audio editors and recording systems.
Software is the catalyst between the VST and the simulation of a traditional recording studio. If you wee to compare the VST plugins with the actual switches and knobs on the actual hardware you would see the similarities. It would then not appear quite so foreign to you if you are familiar with the hard version of the studio equipment. The VST plugins are hosted within a workstation that is a digital audio type.
If you think that there are only a few plugins to choose from, you are mistaken. You are going to be quite surprised to learn there are thousands of various types to choose from. I bet you are thinking about your pocket book right now, but the nice thing is there are may that are freeware, and of course, there are commercial ones available as well.
Being as VST is so popular it’s good to know that there are many audio applications that support them. If you are going to become involved in VST plugins then you will need a VST host. This is just simply a software or hardware application that permit’s the plugins to be loaded and controlled during use. If you shop around you will find some excellent VST host providers.
One of the many cost advantages of using plugins is the fact they really help to cut down your hard based equipment costs. Plus think of the space you can save, not having to store tons of equipment.
You can get some great VST plugins that are like a package deal. For example there is a package available that includes shuffling, panning, panoramas width along with comb filters and many other inclusions as well.
Its important for you to learn that plugins are not software that stand alone. They will usually come with DLL files. This stands for dynamic link library. As we mentioned you can find lots of free software on the internet. It is not difficult to use. You simply follow the instructions for the download. Many of these will walk you through the stages of how to get the best benefits from them.
If you are totally new to the creation of music with your computer then you may want to do some research before you start. It doesn’t mean that you have to do months of learning. In fact, if you start visiting some of the music blogs you will be intrigued at not only how easy it is, but what you can do and create with things like VST plugins.