Category: Managing Servers

We covered installation of a simple wireless Router about a year back. At that time to make the installation as painlessly simple as possible, we have mentioned that we will use WEP – Wired Equivalent Privacy with 128 bit WEP key by using a string of 26 Hexadecimal (Hex) characters.

But WEP is not really suited for a secure Wifi connectivity due to its poor security implementation. With more and more security risks associated with WEP being publicized, it is essential that home and corporate users move on to more secure means.

WPA and WPA2: Wifi Protected Access is a type of system to secure Wireless networks available in 2 modes – Enterprise version and Personal version. The personal version of WPA uses Pre-Shared Key (PSK) in which every computer is given the same passphrase on a shared basis as the name implies. So as a corollary the security of the system depends on the passphrase. In this mode, the data is encrypted using RC4 Stream Cipher with a 128 bit key together with a 48 bit initialization vector. The major security feature is the dynamic changing nature of the Temporal Key integrity protocol. Together with additional security features like Message Integrity Code, WPA provides a better secure Wireless network.

With the technical background covered briefly as above, we again show you how to set up a WPA secured Wireless Access Point in this blog.

We use the same Wireless Router as we have used earlier in our last year example – DLINK DI 524.

• Fire up your Wireless Router’s control panel in your browser. Head to the Wireless button on the left side of the panel. You should be greeted with a  Wireless Settings section of the AP (Access Point) portion.
• Enable the Wireless Radio button
• Select the security to the last option – WPA-PSK/WPA2-PSK mode.

–        The other options include :

–        None (Not Recommended at all)

–        WEP (not recommended again)

Enter a 15 character Passphrase in the PreShare Key column.

Click Apply and exit.

Go to your Laptop or any other Wireless enabled computer and set up the Wireless connectivity. You should be able to browse the list ( depending upon the available Wireless Access point in your locality) and select your now secured Wireless Network by the Network ID (SSID). It should display a dialog box in which the option of providing the PreShare Key is visible. Enter your key here and click to save. I am using a Laptop with Windows Vista Business OS. Your OS may allow you to enter this when you select the Wireless connectivity mode in a slightly different way. But essentially, you will need to enter the same Passphrase across all the computers sharing the same Wireless Network.

And you are ready to Rock and Roll …

What you should know about your IP number ?

Lots of people especially webmasters are familiar with the IP Numbers which identify their unique address in the “stateless world” of Internet. Equally there are many who blink at this term. This blog sets out to unravel the mystery of this in a simple way.

For example the adjacent number (unless you have javascript disabled in your browser) shows your IP address along with some information about the browser type – .

Your IP number identifies your computer – like your physical address. IP (Internet Protocol) Address refers to a set of four octets (numbers) separated by a dot (.). Each octet consists of a number between 0 and 255. There was a popular movie in which the main actor is peering into the monitor of her computer displaying some IP address with one octet as “275”. You can’t have such IP addresses in real life.

Many computer peripherals operate assigned with their own IP addresses to help the users manage them easily. Your network printer can be fed with the document to print by assigning the print task to the particular IP. In the modern networked environment each peripheral or machine can be controlled, monitored and managed in a more effective manner if they have their own Network interface. This also is the main reason why we may face a shortage of available IP numbers in the near future. The current system which uses IPv4 uses 32 bit addresses which has a maximum limit of 4,294,967,296 addresses.

If the entire world is going to be connected to the Net along with their machines, then this IPv4 system simply will run out of available numbers. So they may eventually shift to the IPv6 system in which 128 bit addresses will be used.

To give you an analogy of how things are – we will use a hypothetical physical address like this:

[Note: all addresses given below are imaginary and do not represent anyone]

32, West side Avenue,

San Jose, CA

USA

Class A:

IP numbers are grouped under classes too. Class A represents the first octet like so :

72. xxx.xxx.xxx

This might be like your country code. But each country may have many sets of Class A addresses assigned to them.

Class B:

72.84.xxx.xxx This example shows a typical address which is like your city code.

Class C:

72.84.70.xxx This example shows a typical address which is like your country:city.street address

The last octet represents your machine.

There is one more detail: Many ISPs assign your IP number dynamically using DHCP (Dynamic Host Configuration Protocol). Not all users need the IP addresses permanently. Servers and other mission critical users require permanent dedicated IP addresses while the rest can manage with dynamically assigned ones when they need it.

Now that we have reached your “home” you can specify the connecting port – your entry point to your machine. You can operate many systems assigned to individual ports in the IP address. For example, you can run a web server under port 80 and a mail server under port 25 and so on.

In our firewall blog we have touched upon locking down the ports we don’t use. Using the same physical analogy as above, you secure the windows and doors when they are not normally used. You close the access to the particular ports ( in our case of firewall, we close all the ports unless otherwise required) when not required.

Geotargeting: In these days of highly competitive world, you want to maximize on your advertisement dollars. You don’t want people from Timbuktu to click on your ads targeted at the New York city dwellers. Or you want to maximize the reach of your specific ads to the specific target audience. The easiest way is to use Geotargeting which sends specific pages/ads to specific location based on the visitor IP number. Many search engines use this technique all the time to deliver localized search results.

Next time you see something like the following in your server log file – you are unlikely to be fazed by the IP numbers :

192.168.0.3 – – [28/May/2007:11:31:43 +0530] “GET /cgi-bin/info HTTP/1.1” 200 250 “-” “Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;)”