Wednesday, 23 November 2011

Installation of eBarnamala [Content Management For LTSP]

This post is a reference for the future e-library volunteers who perform the installation of the LTSP server. One of the useful softwares within our e-library deployment is the software known as eBarnamala developed by Nepali developer for nepali schools. While the software itself is very useful for students, most of the volunteers have been complaining about the errors while trying to setup this software. However, the installation of eBarnamala can be simply done by following few simple steps. And this is what I'm writing in this post.

First, due to the different versions(the one with which .py was compiled to .pyc and the python interpreter currently installed in the working system), you might face some bad magic number error. FYI, in the UNIX-like system, filetypes are recognized by the first few bytes of the file which is known as magic bytes. Python also puts the same kind of bytes to ensure they are .pyc files and python interpreter checks for the same number while loading .pyc.

To fix our error, lets delete all the .pyc files in eBarnamala folder. The directory might be different but the commands are the same(except the path). The command for this purpose is as below:

find /opt/eBarnamala/ -name *.pyc -exec rm -f {} \;

Now lets recompile all the *.py files in the eBarnamala folder. Write the following lines of code and save it as somefile.py and later run as "python somefile.py" without quotes.

import compileall
compileall.compile_dir('/opt/eBarnamala/', force=True)

Now lets write a small shell script and save it in the /bin/ folder as eBarnamala(This is absolutely necessary since you'll face errors regarding the loading of images if you do "python /opt/eBarnamala/eBarnamala.py").

cd /opt/eBarnamala/ && python eBarnamala.py

Now you need to copy the fonts from the eBarnamala directory to /usr/share/fonts/truetype.

So you are done. Just create some menu entry or desktop shortcut so that the general users and students can access the software easily. I hope it helps the future e-library volunteers.


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40K Visitors + Giveaway From Techgaun

Cheers from techgaun for our 40,000+ pageviews, to all of you people for your visit, your comments and suggestion and for bookmarking us. with all your kind support, we have made this far.

WE ENCOURAGE YOU TO LEARN AND YOU ENCOURAGE US TO WRITE

To celebrate our 40K+ pageviews, we are having a giveaway. Please read this post for the instructions on how you can participate in the giveaway. Please support us.


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Tuesday, 22 November 2011

How To Check Your Password Strength

With the increase in number of hackers and hack attacks, choosing strong and hard to guess passwords is one of the ways to keep yourself secure. While there are other numerous parameters to take care of to keep yourself secure, one of the primitives is choosing the strong password. In this post, I'll let you know how you can determine the strength of the password you choose to use.

Strength of the password can be tested by studying the character combinations used in the password and there are some tools to assist you in this process.

The first tool is the password strength checker. This online tool gives a very comrehensive detail of the strenght of the password.


Another tool to test the strength of the password is to calculate the bruteforce attack time to retrieve the password from hash. One such tool is a excel template available HERE which gives the estimate of how fast a password is hacked by these widely available tools running on today's desktops. Another online tool for the similar purpose is howsecureismypassword.net which provides bruteforce time and informs if your password is the common one or not.

I hope you find this information useful. :)



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Common Programming Mistakes Beginner Programmers Do

The beginner programmers make some common mistakes which might be due to the lack of practice and deeper understanding of the language syntax and semantics. Here I am listing some of the common programming mistakes every programmer does when s/he is beginner or new to programming.

Mistake #1: Lack of code modularization
Many beginners just write everything within the main function and end up repeating many statements again and again. Rather than having everything within a single main function, you could separate the certain logic in a separate module known as function and then just call that function when needed. If you haven't heard about function, start with google and learn to write some. You'll not regret learning to make functions.

Mistake #2: Another common mistake is not indenting(Read the section Indentation in programming in wikipedia entry) your code and not writing the proper comments in the places wherever necessary. Lack of proper indentation and comments reduce readability. While many compilers and interpreters do not take care about the indentation and comments, human eyes find it easy to understand the properly indented and commented code. Also, some languages such as python rely on indentation where indentation is a must.

Mistake #3: Another common mistake is to use '=' instead of '=='. I've seen this mistake in a lot of codes done by my beginner friends usually in the conditional statements(such as if else) thus resulting in a completely wrong output many times. FYI, '=' is the assignment operator while '==' is the is equal to operator. Note that when '=' is used, the variable on left side of '=' gets set to the value of the expression on the rights. The assignment operator changes the variable on the left to have a new value, while the equal operator '==' tests for equality and returns true or false.

Mistake #4: Integer and float division is also another common mistake every beginner programmer happens to do. In the language like C, the division such as 5/10 will result in 0 since 5 and 10 both are integers and integer division is done. This might lead to mathematical errors in programming. So be sure to typecast the variables to the proper data type before performing division.

Mistake #5: Another common mistake is the use of uninitialized variables. Beginners forget to assign the values to the variables thus giving unexpected outputs such as garbage values in C. Some languages provide default values (such as 0 or null) for uninitialized variables but still using uninitialized variable is a mistake to avoid. Also, many forget to declare the variables thus producing compiler error.

Mistake #6: Another mistake is to compare the strings in C(strings in C are array of characters) using the is equal to '==' operator. Note that string comparison in C requires use of the library functions such as strcmp(), strcmpi() and their safe alternatives such as strncmp() and strncmpi(). Btw, do not use strcmp() and strcmpi() since they do not check length thus might lead to overflow.

Mistake #7: Using wrong range of array indices is also another common mistakes the beginners do. For example, an array of size 10 should be accessed using indices from 0 to 9, not from 1 to 10. Also, some other languages such as Matlab and Fortran, indices will go from 1 to 10. Just make sure you understand the specifications of the language you are learning.

Mistake #8: Using function calls within the looping condition is another mistake. Lets take an example of the following code snippet:

for (i = 0; i < strlen(str); i++) { //do something }


In each iteration, the strlen() function is being called which can slow down your program. So always avoid such calls within the looping conditions.

int len = strlen(str);
for (i = 0; i < len; i++) { //do something }


Mistake #9: Another mistake is the use of insecure and vulnerable functions. If you are going to use certain function, always make a deep study about it to know whether it is secure or not and if it is not secure, search for its secure alternative. Buffer overflows are one of the things you should always try to prevent. Also, if you are doing PHP or other web-based language, always use the safe functions to avoid common security issues such as SQL Injection, Cross Site Scripting, etc. Always research to write secure codes so that you can prevent hackers breaking your code.

Mistake #10: Finally, beginners tend to leave what they are doing if they can not locate errors and mistakes in their code. Just remember studying and practising is the only key to master any stuff which applies to programming as well. You've got such a big resource like internet, so make extensive use of it and never let you go down. Just read and practise and you'll eventually master yourself.

I hope this post helps beginner programmers out there. :)


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Friday, 18 November 2011

Securing LAMPP/XAMPP Installation

LAMPP by default leaves everything open and insecure allowing the possible intrusion to the system. In this post, I will show how you can secure yourself from the possible intrusions if you are using XAMPP and you are in the network. I am using LAMPP, the linux version of XAMPP to demonstrate the steps.

First lets run the security module of LAMPP to impose security in the LAMPP. To fix the security holes, type:

sudo /opt/lampp/lampp security

Now you will be asked with series of passwords if they are open to the intrusion. Check the following session of how I set the passwords for different daemons/services.

samar@Techgaun:~$ sudo /opt/lampp/lampp security
XAMPP: Quick security check...
XAMPP: Your XAMPP pages are NOT secured by a password.
XAMPP: Do you want to set a password? [yes] yes
XAMPP: Password:
XAMPP: Password (again):
XAMPP: Password protection active. Please use 'lampp' as user name!
XAMPP: The MySQL/phpMyAdmin user pma has no password set!!!
XAMPP: Do you want to set a password? [yes] yes
XAMPP: Password:
XAMPP: Password (again):
XAMPP: Setting new MySQL pma password.
XAMPP: Setting phpMyAdmin's pma password to the new one.
XAMPP: MySQL has no root passwort set!!!
XAMPP: Do you want to set a password? [yes] yes
XAMPP: Write the password somewhere down to make sure you won't forget it!!!
XAMPP: Password:
XAMPP: Password (again):
XAMPP: Setting new MySQL root password.
XAMPP: Change phpMyAdmin's authentication method.
XAMPP: The FTP password for user 'nobody' is still set to 'lampp'.
XAMPP: Do you want to change the password? [yes] yes
XAMPP: Password:
XAMPP: Password (again):
XAMPP: Reload ProFTPD...
XAMPP: Done.

I hope this helps to fix the security issues quickly. However, there are other several issues that could be fixed to attain maximum level of security.

EDIT: Check this link for more detailed information than mine.


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Tuesday, 15 November 2011

Blocking Unwanted Hosts, Apps and Adwares With hosts File

Numerous websites and adwares are floating around in the internet which serve as the ad server for providing unwanted, nasty and pop-ads which I hate very much. I knew I could block them from hosts file so I am writing this post once again with the links to the list of such adware servers.

I've previously discussed about blocking websites with hosts file.

Now if you want to block adware servers, you should download a host file with some good lists rather than you working on finding each and every adware sites on your own and adding in the hosts file. A very comprehensive hosts file for download is available at mvps.org. Check my blog post for editing the hosts file.

Few more such hosts file providers are hostsfile.mine.nu and someonewhocares.org.

I hope you find this information useful.


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Stupidity Of Script Kiddie, IRC Transcript

I read this somewhere in the internet a while ago, had it saved in my disk and today I read it again. And I could not stop myself from Lol'ing. So I thought to share this here as well. Read this and you will find it very very funny.

* bitchchecker (~java@euirc-a97f9137.dip.t-dialin.net) Quit (Ping timeout#)
* bitchchecker (~java@euirc-61a2169c.dip.t-dialin.net) has joined #stopHipHop
<bitchchecker> why do you kick me
<bitchchecker> can't you discus normally
<bitchchecker> answer!
<Elch> we didn't kick you
<Elch> you had a ping timeout: * bitchchecker (~java@euirc-a97f9137.dip.t-dialin.net) Quit
(Ping timeout#)
<bitchchecker> what ping man
<bitchchecker> the timing of my pc is right
<bitchchecker> i even have dst
<bitchchecker> you banned me
<bitchchecker> amit it you son of a bitch
<HopperHunter|afk> LOL
<HopperHunter|afk> shit you're stupid, DST^^
<bitchchecker> shut your mouth WE HAVE DST!
<bitchchecker> for two weaks already
<bitchchecker> when you start your pc there is a message from windows that DST is applied.
<Elch> You're a real computer expert
<bitchchecker> shut up i hack you
<Elch> ok, i'm quiet, hope you don't show us how good a hacker you are ^^
<bitchchecker> tell me your network number man then you're dead
<Elch> Eh, it's 129.0.0.1
<Elch> or maybe 127.0.0.1
<Elch> yes exactly that's it: 127.0.0.1 I'm waiting for you great attack
<bitchchecker> in five minutes your hard drive is deleted
<Elch> Now I'm frightened
<bitchchecker> shut up you'll be gone
<bitchchecker> i have a program where i enter your ip and you're dead
<bitchchecker> say goodbye
<Elch> to whom?
<bitchchecker> to you man
<bitchchecker> buy buy
<Elch> I'm shivering thinking about such great Hack0rs like you
* bitchchecker (~java@euirc-61a2169c.dip.t-dialin.net) Quit (Ping timeout#)
* bitchchecker (~java@euirc-b5cd558e.dip.t-dialin.net) has joined #stopHipHop
<bitchchecker> dude be happy my pc crashed otherwise you'd be gone
<Metanot> lol
<Elch> bitchchecker: Then try hacking me again... I still have the same IP: 127.0.0.1
<bitchchecker> you're so stupid man
<bitchchecker> say buy buy
<Metanot> ah, [Please control your cussing] off
<bitchchecker> buy buy elch
* bitchchecker (~java@euirc-b5cd558e.dip.t-dialin.net) Quit (Ping timeout#)
* bitchchecker (~java@euirc-9ff3c180.dip.t-dialin.net) has joined #stopHipHop
<bitchchecker> elch you son of a bitch
<Metanot> bitchchecker how old are you?
<Elch> What's up bitchchecker?
<bitchchecker> you have a frie wal
<bitchchecker> fire wall
<Elch> maybe, i don't know
<bitchchecker> i'm 26
<Metanot> such behaviour with 26?
<Elch> how did you find out that I have a firewall?
<Metanot> tststs this is not very nice missy
<bitchchecker> because your gay fire wall directed my turn off signal back to me
<bitchchecker> be a man turn that shit off
<Elch> cool, didn't know this was possible.
<bitchchecker> then my virus destroys your pc man
<Metanot> are you hacking yourselves?
<Elch> yes bitchchecker is trying to hack me
<Metanot> he bitchchecker lame if you're a hacker you have to get around a firewall even i can do that
<bitchchecker> yes man i hack the elch but the sucker has a fire wall the
<Metanot> what firewall do you have?
<bitchchecker> like a girl
<Metanot> firewall is normal a normal hacker has to be able to get past it...you girl^^
<He> Bitch give yourself a jackson and chill you're letting them provoce you and give those little
girls new material all the time
<bitchchecker> turn the firewall off then i send you a virus [Please control your cussing]er
<Elch> Noo
<Metanot> he bitchchecker why turn it off, you should turn it off
<bitchchecker> you're afraid
<bitchchecker> i don't wanna hack like this if he hides like a girl behind a fire wall
<bitchchecker> elch turn off your shit wall!
<Metanot> i wanted to say something about this, do you know the definition of hacking??? if he turns
of the firewall that's an invitation and that has nothing to do with hacking
<bitchchecker> shut up
<Metanot> lol
<bitchchecker> my grandma surfs with fire wall
<bitchchecker> and you suckers think you're cool and don't dare going into the internet without a
fire wall
<Elch> bitchchecker, a colleague showed me how to turn the firewall off. Now you can try again
<Metanot> bitchhacker can't hack
<Black<TdV>> nice play on words ^^
<bitchchecker> wort man
<Elch> bitchchecker: I'm still waiting for your attack!
<Metanot> how many times again he is no hacker
<bitchchecker> man do you want a virus
<bitchchecker> tell me your ip and it deletes your hard drive
<Metanot> lol ne give it up i'm a hacker myself and i know how hackers behave and i can tell you
100.00% you're no hacker..^^
<Elch> 127.0.0.1
<Elch> it's easy
<bitchchecker> lolololol you so stupid man you'll be gone
<bitchchecker> and are the first files being deleted
<Elch> mom...
<Elch> i'll take a look
<bitchchecker> don't need to rescue you can't son of a bitch
<Elch> that's bad
<bitchchecker> elch you idiout your hard drive g: is deleted
<Elch> yes, there's nothing i can do about it
<bitchchecker> and in 20 seconds f: is gone
<bitchchecker> tupac rules
<bitchchecker> elch you son of a bitch your f: is gone and e: too
<bitchchecker> and d: is at 45% you idiot lolololol
<He> why doesn't meta say anything
<Elch> he's probably rolling on the floor laughing
<Black<TdV>> ^^
<bitchchecker> your d: is gone
<He> go on BITCH
<bitchchecker> elch man you're so stupid never give your ip on the internet
<bitchchecker> i'm already at c: 30 percent
* bitchchecker (~java@euirc-9ff3c180.dip.t-dialin.net) Quit (Ping timeout#)


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Top Computer Jokes That Will Make You Laugh

Today I was feeling lazy and read some computer related jokes to pass my time. Here I am posting few of the jokes that will make you laugh all the time you read.

ENGINEERS AND ACCOUNTANTS. A novel approach to saving money.

Three engineers and three accountants are traveling by train to a conference. At the station, the three accountants each buy tickets and watch as the three engineers buy only a single ticket.

"How are three people going to travel on only one ticket?" asks an accountant.

"Watch and you'll see," answers an engineer.

They all board the train. The accountants take their respective seats but all three engineers cram into a restroom and close the door behind them. Shortly after the train has departed, the conductor comes around collecting tickets. He knocks on the restroom door and says, "Ticket, please."

The door opens just a crack and a single arm emerges with a ticket in hand. The conductor takes it and moves on.

The accountants saw this and agreed it was quite a clever idea. So after the conference, the accountants decide to copy the engineers on the return trip and save some money (being clever with money, and all that). When they get to the station, they buy a single ticket for the return trip. To their astonishment, the engineers don't buy a ticket at all.

"How are you going to travel without a ticket?" says one perplexed accountant.

"Watch and you'll see," answers an engineer.

When they board the train the three accountants cram into a restroom and the three engineers cram into another one nearby. The train departs. Shortly afterward, one of the engineers leaves his restroom and walks over to the restroom where the accountants are hiding. He knocks on the door and says, Ticket, please."

An artist, a lawyer, and a computer scientist

An artist, a lawyer, and a computer scientist are discussing the merits of a mistress. The artist tells of the passion, the thrill which comes with the risk of being discovered. The lawyer warns of the difficulties. It can lead to guilt, divorce, bankruptcy. Not worth it. Too many problems. The computer scientist says "It's the best thing that's ever happened to me. My wife thinks I'm with my mistress. My mistress thinks I'm home with my wife, and I can spend all night on the computer!"

Only Errors, No Warnings

A man is smoking a cigarette and blowing smoke rings into the air. His girlfriend becomes irritated with the smoke and says, “Can’t you see the warning on the cigarette pack? Smoking is hazardous to your health!”

To which the man replies, “I am a programmer. We don’t worry about warnings; we only worry about errors.”


Speed Of New Super Computers

Have you heard about the new Cray super computer? It’s so fast, it executes an infinite loop in 6 seconds.

Two types of people

There are two types of people in this world: those who understand recursion and those who don’t understand that there are two types of people in this world:

Gates and Marc Andressen In Heaven
Bill Gates and Marc Andressen (from Netscape for those who don’t know) die and go to heaven. Peter meets them and announces that they will get stabbed with a needle for each major bug in their browser software. First it’s Marc’s Turn: “In Navigator 1.0 there was a big security hole” PRICK! “In Navigator 1.1 you couldn’t empty the cache” PRICK! Marc rubs his butt and looks around: “Where did Bill go?” Peter says in reply: “He’s just being clamped into the sewing machine…”


Note: All the jokes are taken from various online sources where I read them.


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