COSIMS Blog

The cosims held a gaming competition. It was a fun event to organize; photos will be soon put here to show you how we play :).
All the games gone really grate (Counter Strike and Need For Speed Underground 2)
Now planing for programing competition lets see where it goes.
Congratulations to the winner



1. Counter Strike Won by Night Strikers


2. Need For Speed Underground 2 Won by Arsalan
3. Girls Event : Won by Ammara Paracha and Mehwish Malik 


                                        Regards;
                                                 President COSIMS

COSIMS Arranged Seminar on VOIP

These are some collection of photos:)

Dear all i recently was not able to write stuff here because i got busy :)








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Preface

Dear reader, in the following page I will teach you about ip addresses. Understanding ip address concepts is very important for any hacker or a computer networking professional. Please note that this tutorial is for beginners.



Contents-

• What is an ip address
• 
  
• IP addressing system
• 
  
• What is my ip address?
• 
  
• More about IP Addresses
• 
  
• A B and C Class networks
• 
  
• Getting ip address of other computers
• 
  
• Getting IP address of visitors of your site
  

The tutorial begins. . .

What is an ip address and uniqueness of ip addresses

Every computer has its own ip address. This address must be unique for a particular network. Let suppose there is a LAN ( Local Area Network ) . In a LAN we connect 2 or more computers together to make a network so that they can share one or more services. A typical example is the network of a school or of a cyber cafe where computers are connected to share hard disk and internet connection respectively. Now consider a computer on  a LAN. To communicate to other computers it must have a unique ip address. If two computers have the same ip address they both or one of them won't be able to work on network because  every computer on any network communicates with other computer using ip address and if two computers have the same ip address , other computers won't be able to figure out that to which of the two computers they have to communicate as both of them have the same ip address.IP addressing system
Every ip address is of the form abc.def.ghi.jkl
For example 192.168.1.160 is a valid ip address. There are four octets in an IP address. The maximum value that a octet can have is 255 and minimum is 0. In our example 192 is the first octet . 0 is the second one and so on. An ip address is a 32 bit address. Let me change this ip address to bit format . The bit format of the above ip address is
11000000 10101000 00000001 10100000
Now as I know the binary arithmetic I have transformed this ip address. If you don't know the binary arithmetic don't worry I will teach a simple way of doing this. Just start windows calculator by clicking on Start then clicking on Run.. and type calc and press the OK button . A new window will pop up that and that is a windows in built calculator. If you are running this for first time you will be shown Standard view . Switch to Scientific view by click on View on Menu bar and then selecting scientific .
To change the number 192 to bit format just type 192 and then select bin on the left half of the calculator. The calculator will display the bit format.
Now there are other formats like octal and hex but we need not go in details . Just remember that  ip address of  a computer remains same regardless of the format . So  connecting to a computer  having an ip address 192.168.1.160 is same as connecting to a computer having ip address C0.A8.1.A0 (in the octal format)

What is my ip address?
Now  you understand that every computer has its own ip address regardless whether it is on a network or not . You must the thinking that if a computer is not on a network then why it will require an ip address and what is the ip address of this computer. IP address is required not only for communicating to other computers but also for one more reason . There are many softwares that require to test themselves whether your computer has capability to connect to internet so there is a 'built in' ip address known as Loop Back ip address that always refer to the computer you are working on. This ip address is 127.0.0.1
Now you want to know your ip address. If you are not working on a LAN you may use the inbuilt windows utility known as WINIPCFG . To run this program Click on Start and click on RUN...and type winipcfg and press OK .
You will be able to see your ip address in the utility . Please note that if you are not connected to internet you will see your ip address as 127.0.01 and is you are connected to internet you will see the ip address as provided by the ISP . The ip address provided by the ISPs generally change each time you connect.If you are working on a LAN you are having your own LAN ip. To find it out first find out your computer name . To do so right click on Network Neighborhood and click on properties and then click on Identification tab . Your computer name is shown there. Let suppose your computer name is COMPUTER1
Open command prompt by clicking on Start then moving to Programs and then clicking on  Command Prompt. You will get the command prompt as 
C:\windows>
To toggle to full screen mode and window mode please use the key combination ALT+ENTERTo exit command prompt type exit and hit enter key.Just type in the command
C:\windows>tracert COMPUTER1
please change COMPUTER1 to the name you get in the identification tab of the properties of Network Neighborhood . You will get the result
Tracing route to COMPUTER1[192.168.0.1]
over a maximum of 30 hops:

1   <1 ms  <1 ms  <1 ms  [192.168.0.1]
Trace complete.
The numbers in the brackets 192.168.0.1 is your LAN ip. Your LAN ip may be different . Alternatively you can use winipcfg to view the ip address but the above method is a general method that can be used to get the ip address of any computer on a LAN
I have assumed that you are using windows 98 . If you are using Windows NT  the process will remain same except that command prompt may look some what different.

                                          MORE ABOUT IP ADDRESSES

Every ip address consists of two parts - a network address and a host address . All computers in a network have the same network address and while the host address is unique to the computer only .The network address can occupy one to three octets from the left while the rest are reserved for host . For example , the ip address 192.168.0.1 has the host address 1 and the network address as 192.168.0 . You may think that this network can support 256 hosts(0 to 255) but in reality it can support 254 hosts because 0 and 255 are reserved.
          A B and C Class networks
The number of octets reserved for the network address and the value of first octet determine the class to which the network belongs. The internet divides network into mainly three classes.
Class A address-
NOTE - N stands for network address and H for host address.
This address takes the form N.H.H.H . The N (network address is setup by NIC) and H by network administrator. If a US network is connected to the internet the network address has to be allotted by InterNIC - a body that distributes network addresses. N here takes values from 1 to 127. Columbia university has the value 15 . These address were allotted to very large organizations but are not longer assigned now.
Class B address- It uses the first two octets as network address.
Last two octets are used for host address. It can take values from 128 to 191. Many ISPs use this class.
Class C address-
Here the network address uses the first three octets and last one is used for host address. The first octet varies from 192 to 223. This class is used by small networks.In short, we have

                             Class                                           Range

                                A                             0.0.0.0 to 127.255.255.255

                                B                             128.0.0.0 to 191.255.255.255

                                C                             192.0.0.0 to 223.255.255.255

                                D                             224.0.0.0 to 239.255.255.255

                                E                             240.0.0.0 to 247.255.255.255

                                       Getting ip address of other computers
You can easily get the ip address of websites. Lets us take an example.
Suppose you want to get the ip address of www.yahoo.com . To do so simply launch MS-DOS command prompt and type ping www.yahoo.com . You will get the following response.
C:\windows>ping www.yahoo.com

Pinging yahoo.com [216.115.108.245] with 32 bytes of data:

Request timed out.

Request timed out.

Request timed out.

Request timed out.

Here 216.115.108.245 is the ip address of www.yahoo.com
Similarly if you want to get the ip address of a computer named comp1 on  a LAN make sure that you are also on that LAN and then type ping comp1 at the command prompt and you will get the ip address of comp1.
Now let suppose you want to get the ip address of your friend's computer who is online. Here are the methods.
                                                 Using ICQ
Just ask your friend to join you on ICQ and start chatting with him , while you are chatting launch MS-DOS command prompt and type netstat -n and you will get the ip address of your friend. Please note that you should not use any other internet related software because that can add one more ip address in the output of netstat -n command. Here is a sample output
Active Connections

Proto     Local Address      Foreign Address           State
TCP     192.168.0.1:3537   203.195.136.156:2869   ESTABLISHED   
In this case 192.168.0.1 is your ip address and 203.195.136.156 is the ip address of your friend.
                                      Using MSN and YAHOO MESSENGERS
In case of these messengers direct connection is not established between the two persons who are chatting instead the messages are sent via Yahoo or MSN messenger servers. So if you use the netstat -n command you will not find the ip address of your friend but of Yahoo or MSN messenger servers. Lets play a trick. Just ask your friend that you are sending him some important file via SEND FILE option of your messenger. While the file is being transferred run command netstat -n and you will find that a new ip address is listed there. This is the ip address of your friend because in case if a file is transferred via SEND FILE option of messengers a direct connection is made between your computer and yours friend computer.                                   GETTING IP ADDRESS OF VISITORS OF YOUR SITE
If you have a site , you may wish to record the ip address of the visitors who view your webpage. To do so you may include following script in the HTML code of your webpage

HTML

BODY

SCRIPT

 var ip = new java.net.InetAddress.getLocalHost();

 var ipStr = new java.lang.String(ip);

 document.writeln(ipStr.substring(ipStr.indexOf("/")+1));

 SCRIPT

BODY

HTML

After using Internet Explorer for many years, I have to say that I really wish I would have switched to Firefox a lot earlier than I did! Firefox is by far the most customizable browser out there, with thousands of extensions and addons that you can download and plug in. Not only are there many third-party extensions to enhance Firefox, there are also tons of configuration settings that can be tweaked in Firefox itself.
Over the last few months, I’ve tweaked a good number of settings in Firefox and I thought I would share it with my Firefox readers. That way you can truly make Firefox YOUR browser. I’m going to go through a couple of Firefox about:config settings that you can change that made my browsing experience more enjoyable.

How to backup about:config file

Before you begin editing the about:config file in Firefox, you should back up the file in case you make a change that messes everything up. You can back it up by making a copy of the prefs.js, which is in the Firefox profile folder. For Windows, you will have to show Hidden Files and Folder by opening Control Panel, double-click Folder Options, select the View tab, select “Show hidden files and folders” and click OK.
For Windows XP
\Documents and Settings\username\Application Data\Mozilla\Firefox\Profiles\ .default\
For Windows Vista
Users\username\AppData\Roaming\Mozilla\Firefox\Profiles\.default\
For Mac OSX
username/Library/Application Support/Firefox/Profiles/profile.default/
For Linux
~/.mozilla/firefox/profile.default/

How to modify the about:config configuration in Firefox

First off, it’s probably a good idea to mention how to actually modify these advanced configuration settings in Firefox for those non-techie users. The configuration settings are simply a table of key names and values. You can access all of them by typing in about:config into your browser address bar.

To change a value for a key, simply enter it’s name into the Filter text box at the top. Double click on the entry and you can change the value. Restart the browser and the changes will take effect. So here are the tweaks:

Configure close button on Firefox tabs

Don’t you hate it when you’re trying to close one tab and you end up closing the one right next to it? Pain in the butt and very common (at least for me). You can control the close button on the tabs by changing the following key:

browser.tabs.closeButtons

0: Display a close button only on the currently active tab. A good way to prevent the closing of other tabs.
1: Display close buttons on all tabs (default).
2: Don’t display any close buttons; you have to press Ctrl-F4 to close a tab.
3: Display one close button at the end of the tab bar (Firefox 1.x’s default).

Increase number of tabs that can be displayed

Tabbed browsing is great and I’m such a big user of it that I end up having about 20 tabs open most of the time. By default, if you have more than 12 tabs open, Firefox will set the tabs to a specified width and then scroll the rest with arrows. One way to see more tabs if you’re a power tab user is to decrease the width of the Firefox tabs so that more can fit before scrolling starts. The default is 100 pixels, so you can choose something less to see what works best for you.
browser.tabs.tabMinWdith
100 pixels default value

 

Open search results in a new tab

This tweak is pretty cool and one of the best out there. Basically, when you perform a search from the search box at the top right in Firefox, it normally loads in the current tab. However, if you set the value of this setting to TRUE instead of FALSE, then every time you perform a search, a new tab will come up with the results, thereby leaving your current tab alone!
browser.search.openintab
False - Default value, set to True to load results in a new tab

Download and cache only pages you actually view

Firefox has an interesting feature whereby it tries to determine which links on a page you might click on and then downloads them so that it can load the pages faster. For example, it will try to download the top result from a Google search automatically. However, this eats up bandwidth and CPU cycles and saves web history of pages you may have never even visited! To turn it off, set the value to false.
network.prefetch-next
True – Default value, set it to False

Increase number of simultaneous downloads and connections to a server

From the networking point of view, you can increase a couple of different settings to increase network performance. network.http.max-connections controls how many simultaneous network connections Firefox will make at any one time to any number of Web servers. Default is set to 24, but you can knock it up to 32 to see if that has any effect. Anything above that will not do much.
network.http.max-connections-per-server controls how many separate connections Firefox makes to the same server, which allows for multiple elements to be download in parallel. Only do this if you have a fast connection and don’t raise it by too much otherwise you will be blacklisted. The default is 8 and you should only increase it by a few.
network.http.max-persistent-connections-per-server controls the number of persistent connections allowed per server. The default is 2 and this is generally the value people list when they are say you can increase the number of simultaneous downloads in Firefox. Again, don’t go more than 1 or 2 above the default as you could be temporarily blacklisted.

Turn off those annoying tool tips

Finally, you can get rid of all of those annoying tool tips that pop up every time you hover your mouse over a button by changing the config file. Personally, I already know what every single button on my toolbar does and it annoys me when they pop up and cover something else!
browser.chrome.toolbar_tips
True – Default value, set it to False to turn off tool tips

Use a custom search engine for the address bar

By default, if you type in a phrase that is not a web address into the address bar, Firefox sends the query to Google for a web search. You can change this so that it uses a different search engine if you prefer.
For Windows Live search:
http://search.live.com/results.aspx?q=
For a Yahoo search:
http://search.yahoo.com/search?p=
To go back to the default:
http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=
keyword.URL
Change to any of the following above to use a different search engine.
You can also check out the Mozilla page for a complete list of configurations that you can change with descriptions at about:config wiki page. Any other about:config changes that you like? Post a comment!