Let's see how to configure the FreeRADIUS2.x application to respond with an Access-Challenge for incoming Access-Request messages using the rlm_perl module scripting

System Specifications:

Ubuntu 12.04 LTS (i686 i686 i386 GNU/Linux)
FreeRADIUS v2.1.10

Configuration:

Step 1:

Edit the “clients.conf” file in the /etc/freeradius directory and add the Client's IP details as below

client 192.168.3.33 {
 secret = testing123   < -- Shared secret between Client and Radius server
 shortname = NodeToBeAuth
 netmask = 32
}

Step 2:

Edit the “users” file in the /etc/freeradius directory and add the users to be authenticated as below

user1 Auth-Type := Perl   < -- Use rlm_perl module for Authentication
user2 Cleartext-Password := "abc#123"  < -- Use plain text password for Authentication

Step 3:

Edit the “perl” file in the in the /etc/freeradius/modules directory and specify the script you would like to execute when the Auth Type is set to Perl as above in the users file

perl {
 module = ${confdir}/challenge.pl < -- Perl script on the /etc/freeradius directory
}

Step 4:

Enable the rlm_perl module by editing the “inner-tunnel” and the “default” files in the /etc/freeradius/sites-available directory as follows. Add the perl module under the authenticate section so that the perl module will be included and loaded when FreeRADIUS is started

authenticate {
 Auth-Type Perl {
  perl
 }
.
.
.
.
}

Script for Authentication:

Copy the example code posted on the official FreeRADIUS website and paste into a file named as challenge.pl in the /etc/freeradius directory

http://wiki.freeradius.org/modules/Rlm_perl

Edit the subroutine authenticate() as follows

# Function to handle authenticate
sub authenticate {
    # For debugging purposes only
    if ($RAD_REQUEST{'User-Name'} =~ /^baduser/i) {
            # Reject user and tell him why
             $RAD_REPLY{'Reply-Message'} = "Denied access by rlm_perl function";
             return RLM_MODULE_REJECT;
    } else {        < -- Any user except a bad user
            # Accept/Challenge user and set some attribute
  $RAD_REPLY{'State'} = "some state code here";
              $RAD_REPLY{'Reply-Message'} = "Enter the pin number";
  $RAD_CHECK{'Response-Packet-Type'} = "Access-Challenge"; < -- Send challenge back
  return RLM_MODULE_HANDLED;
    }
}

The above logic can be extended for the case of a user responding to the Access-Challenge by handling the condition of verifying the user response to the challenge found in the RADIUS attributes of the response message

Verification:

Start the RADIUS server in debug mode. Make sure that no freeradius daemon already running in the background before starting the server

# freeradius –X
{or}
#LD_PRELOAD=/usr/lib/libperl.so.5.14 /usr/sbin/freeradius –X  < -- Ubuntu 12.04 bug

Now test plaintext password authentication for user 2 as below

# radtest user2 abc#123 127.0.0.1 0 testing123
Sending Access-Request of id 203 to 127.0.0.1 port 1812
    User-Name = "user2"
    User-Password = "abc#123"
    NAS-IP-Address = 127.0.1.1
    NAS-Port = 0

rad_recv: Access-Accept packet from host 127.0.0.1 port 1812, id=203, length=20
Now test challenge authentication for user 1 as below
# radtest user1 doesntmatter 127.0.0.1 0 testing123
Sending Access-Request of id 33 to 127.0.0.1 port 1812
    User-Name = "user1"
    User-Password = "doesntmatter"
    NAS-IP-Address = 127.0.1.1
    NAS-Port = 0

rad_recv: Access-Challenge packet from host 127.0.0.1 port 1812, id=33, length=60
    Reply-Message = "Enter pin number"
    State = 0x736f6d6520727461746524636f66652068657265

Please note that we are doing this testing using localhost (127.0.0.1) and the NAS-IP-Address should point to the RADIUS server IP address for remote RADIUS server. Please refer to the wiki page of FreeRADIUS for configuration details of FreeRADIUS 3.x or higher

References:

http://wiki.freeradius.org/modules/Rlm_perl

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Bluetooth RSSI - Nexus7 & Nokia Xpress Music

Client:

public void PollRSSI()
{
try {
while(true)
                 {
        try {
        System.out.println();
        if(Android_Device != null)
        System.out.println("Android RSSI = " + RemoteDeviceHelper.readRSSI(Android_Device));
     } catch (Exception e) { System.out.println("Android RSSI = Connection Error"); }
        try {
        if(Nokia != null)
        System.out.println("Nokia RSSI = " + RemoteDeviceHelper.readRSSI(Nokia));
      } catch (Exception e) { System.out.println("Nokia RSSI = Connection Error"); }   
        Thread.sleep(2000);
                }
     } catch (Exception e){ e.printStackTrace(); }
}

Server:

public AcceptThread()
{
                   BluetoothServerSocket tmp = null;
                   mBluetooth = BluetoothAdapter.getDefaultAdapter();
                   mUuid = UUID.fromString("00000003-0000-1000-8000-00805F9B34FB");
        try {
                tmp = mBluetooth.listenUsingInsecureRfcommWithServiceRecord("BluetoothCustomService",      mUuid);          
             } catch (IOException e) { }
                myServerSocket = tmp;
         }

public void onCreate()
{
super.onCreate();

thread1 = new Thread(new AcceptThread());
thread1.start(); //First thread will often be denied
thread2 = new Thread(new AcceptThread());
thread2.start(); //Most probably be accepted

}


Source Code:

BluetoothRSSIPollingClient.java       AcceptThread.java       BluetoothRSSIService.java

References:

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BenchMarks_Little.tar.gz

compress95:


go:


anagram:


cc1:


perl:


References:

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Notable Aspects:

• Each server in the cluster stores the session object data in its RAM and does not write it to disk for obvious reasons
• No code change or new code has to be incorporated by the programmer and all that is needed is to change a configuration setting in order to activate velocity caching
• Distributed caching means multiple web servers can each run an instance of the same application which helps in load balancing
• Both web server (IIS) and cache server (Appfabric) can be deployed on a single application server running on Windows Server OS
• Turning on the high-availability feature helps mitigate situations when a server in the cluster goes down by storing a synchronous secondary copy of the data item on a different server

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Lava A9 Dual Sim Phone is a handsome instrument with an assortment of useful features and applications at an affordable price. The phone looks solid with a hard metal body and a smooth keypad which gives an elegant appearance to the phone. Lava A9 comes with a 3.2MP camera that lets you take pictures and shoot videos but the image quality is very poor and doesn't live up to the expectations of a 3.2MP camera. The zooming option is also limited and the camera is a big let down in A9. There is 64MB internal phone memory and the phone will support up to 8GB Micro SD Cards. Listening to music on this phone is not a pleasant experience on the loud speaker but the audio quality is slightly better while hearing it on the ear phone. FM reception is also not satisfactory.

Having said the above glitches in the phone, Lava A9 is otherwise an excellent phone with an impressive profile. The phone comes with both EDGE and GPRS support enabling you to connect with the internet through the pre-installed Opera Mini web browser. Nimbuzz is a refreshingly new application that comes pre-installed with Lava A9 with which you can make calls or chat with your friends over the internet sans the conventional call charges. The phone with a user friendly interface has all the features we expect including bluetooth, java games, Ebook reader, Email support, MP3/MP4 Player, etc. Apart from the usual audio and video recorder the phone also lets you record streaming FM audio in any of the three formats WAV/AWB/AMR. You can also search your contacts with phone number as the search criterion which is handy at some situations. You can also integrate the phone with your PC with the help of Lava A9 PC Suite that can be downloaded from LavaMobiles.com website. Apart from the camera and loud speaker anomalies, LAVA A9 is a good looking phone with powerful features and provides value for money.

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I had a chance to handle this phone after my friend bought it last week. As far as the design is concerned, holding the phone in my palms was a bit awkward considering the width (56.5 mm) of the phone but it is an advantage when it comes to a bigger screen experience. The phone with a plastic body is light weight but still sturdy and looks plain and simple. From the design perspective there is a dedicated keypad lock/unlock button on the right side. Virtual keypad means minimum buttons on the front panel and maximum screen size. The capacitive touchscreen performs well and the interface is intelligently designed for easy navigation of menu items. The menu icons can be docked on the left side for quick access or pulled out from the menu which spans 3 pages that can be easily flicked through. The 2MP camera shoots well in good lighting conditions and the single finger image zoom option is handy while viewing pictures. The phone has a gamut of applications and widgets to integrate with the internet and the social networking world. The sound quality is good and watching videos in a wide screen is comforting as well.

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In software engineering profession everyday new challenges and problems turn up in the blink of an eye and as engineers we are obliged to resolve them ASAP. One of the biggest challenges in the IT industry today is handling data that is vast and increasing everyday. Data is normally stored in databases in the form of tables and a common situation while handling databases is to transfer data from one table to another.

Case I: If both tables reside in the same database server

Consider the case where you want copy the data from Table_1 under Schema_1 into Table_2 under Schema_2. A simple sql command to do this operation would be

INSERT INTO DB_Name.Schema_2.Table_2
SELECT * FROM DB_Name.Schema_1.Table_1 WHERE [condition]

If you want to insert only certain columns you can slightly tweak the command accordingly

INSERT INTO DB_Name.Schema_2.Table_2(COL1, COL2, ....COLn)
SELECT COL1, COL2, ....COLn FROM DB_Name.Schema_1.Table_1 WHERE [condition]

Case II: Load a table from a file

Consider the situation where you want to load a table from a delimited file. This can be done using the BULK INSERT command in Transact-SQL. In order to perform this operation you need access to the file present in the database server. CSV (Comma-seperated values) is a common format used to store the data from a table or spreadsheet. To load a database table from a .csv file use the following command

BULK INSERT Table_Name
FROM 'C:\Program Files\File.csv'
WITH
(
FIELDTERMINATOR = ',',
ROWTERMINATOR = '\n'
)

Bulk insert command provides a slew of options to load a table from a simple delimited text file or even from an xml file.

Case III: If both tables reside in different database servers

The bcp Utility is an excellent command line tool to transfer table data between two different database servers swiftly across a network. You can use bcp to extract table data by querying the table and store it in a delimited file. You can then load the other table from this delimited file easily using a simple bcp command. You don't even have to login to the servers to access the files.

bcp DB1.SCHEMA1.TABLE1 out FILEPATH -n -S[server_name\instance_name] -T -e[error_filepath]
bcp DB2.SCHEMA2.TABLE2 in FILEPATH -n -S[server_name\instance_name] -T -e[error_filepath]

-n uses the native (database) data types
-S should be added before server name
-T using a trusted connection
-e should be added before filepath for error file that logs the failed rows

The first command extracts the rows from TABLE1 and stores in the appropriate FILEPATH (eg. C:\Program Files\File.csv) in the database server. The second command loads TABLE2 with the data present in the File.csv. You have to run the first command to create the file first and then run the second command to load the data into the table. Instead of selecting the entire table you can also include your own select query within the bcp command. BCP offers a legion of options to transfer data between tables in different modes and formats.

Alternately you can also make use of Data Transformation Services (DTS)/ SQL Server Integration Services (SSIS) package in order to consolidate data from heterogeneous data sources.

Useful Resources:

bcp Utility - http://msdn.microsoft.com/en-us/library/ms162802.aspx
bulk insert - http://msdn.microsoft.com/en-us/library/ms188365.aspx

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Virtual Memory is a cost effective solution to slake the thirst of memory hungry applications for a seamless experience with your operating system. To understand the concept of virtual memory you need a little knowledge about the memory organization and working. There are basically two types of memory you need to know. Random Access Memory (RAM) is faster but costly. Memory like hard disk is slower but relatively cheaper. Virtual memory is a stratagem to utilize the hard drive memory to achieve enhanced performance from the random access memory.

Whenever you run multiple programs/applications in your desktop, you will be working on only a portion of a particular application at an instant. Therefore it is a waste of resource to load the entire memory required for a particular application into the limited size random access main memory. In a virtual memory environment each page of a process is brought to main memory only when it is needed on demand.


Data is stored in any memory in the form of binary digits. The operating system handles memory management in the form of chunks of memory called pages. A page is nothing but a contiguous block of memory. One process might require multiple pages of memory but only a few pages might be active at a time. Virtual memory uses a technique called demand paging to effectively use the available RAM memory. Every page has an address which may be a virtual or logical address. The main memory is divided into equal size chunks called page frames and each page frame has a unique physical address. So whenever a page needs to be accessed, the operating system has to translate the virtual address into a physical address and this is done by a Memory Management Unit (MMU) with the help of mapping in a page table. The virtual address corresponding to a page is mapped to a physical address corresponding to a page frame in main memory. Whenever a page is not in memory the operating system fetches the page from hard disk in response to a page fault exception. The operating system usually makes a prediction based on past history using intelligent algorithms regarding those pages that are least likely to be needed again and places them in the hard disk.

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Assisted GPS is an improved version of conventional GPS and it has revolutionized mobile navigation systems across the globe. The A-GPS system relies upon an assistance server to accurately resolve the location of a device. A-GPS system is commonly used in mobile phones to provide real time navigation services. The Global Positioning System works on the principle of trilateration to determine the coordinates of a point on earth. In this principle a satellite is considered to be at the center of a sphere and the mathematical treatment of three such spheres/satellites gives the intersections of the spheres which are used to determine the coordinates. By including one more sphere/satellite in the analysis the point can be located more precisely. The distance between the point on earth and the satellite is computed by transmitting a packet of data tagged with the sent time and by subtracting this from the time the packet was received, we get the time of transit. Assuming the packet traveled at the speed of light, we can estimate the distance of the satellite which serves as the radius of the sphere.
The standalone GPS system is susceptible to atmospheric conditions and multipath errors which tend to prolong the time to first fix. This is not appropriate for real time navigation and emergency applications. A-GPS offers a solution to this problem with an architecture that makes use of data connectivity to an Assistance server located at a place with strong signal connectivity with the satellites. There are two possibilities here.

• The assistance server may transmit orbital parameters and atomic time information to the mobile phone via the network. The GPS receiver in the mobile phone correlates this data with the fragmentary data received directly from the satellites thereby increasing its sensitivity and resulting in a quicker time to first fix.
• The mobile phone with limited processing capabilities can delegate the processing function to the more sophisticated assistance server by sending the weak fragmentary data to the processing server that has good satellite signal and receive the position information from the server through the network.

A-GPS is a feasible option to provide navigational services in an urban environment with tall buildings and high radio interference. On the flipside the service provider will charge the subscriber for network data traffic using GPRS/3G.

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I encountered a peculiar problem in a shell script that was used to find the yesterday's and tomorrow's date using the environmental variable TZ. The script that was previously written to find yesterday's date on a server that was located in EDT time zone was

YesterdayDate=`TZ="EDT+24" date`

But unfortunately the code failed to give the correct date of yesterday and instead it gave today's date. I thought of digging deep into this issue and logged in to a linux server to investigate the matter. After some long manipulations I observed something.


BST is 1 hour ahead of UTC $ YesterdayDate=`TZ="BST+23" date`

The script "EDT+24" gave only GMT/UTC time and inorder to get the correct timezone I needed to add the offset value for the particular time zone. After I made the changes the script seems to be working fine.

EDT is 4 hours behind of UTC $ YesterdayDate=`TZ="EDT+28" date`

CDT is 5 hours behind of UTC $ YesterdayDate=`TZ="CDT+29" date`

MDT is 6 hours behind of UTC $ YesterdayDate=`TZ="MDT+30" date`

PDT is 7 hours behind of UTC $ YesterdayDate=`TZ="PDT+31" date`

I'm still a bit confused as to why the $TZ is behaving so unexpectedly.

Note: I'm just a novice and not an expert in Unix or Shell Scripting. I just wanted to share my experience with timezones on linux servers.

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Last week I wanted to buy a mobile phone for my father and I was hunting for an economical music phone with camera and GPRS. Since I was buying it for my dad, I preferred Nokia because of the user friendly interface their phones have. When I inquired my friends, almost everyone suggested the Nokia 5130 Xpress music phone. I was convinced with the looks of the phone and bought it.

Pros

The Price of the phone is the crowd puller. With a 2.0 Megapixel Camera, 1GB microSD card storage, Bluetooth, GPRS and a sleek design, Nokia 5130 is a smart buy option.

I would give 9 out of 10 for the design and form factor. Everything is neatly packed, smoothly finished and custom fabricated with the buttons ideally located for a perfect music phone. The backlighting effect is appreciated.

I'm a person who prefers phones with a bigger display. Nokia 5130 display area is not the largest ever but definitely satisfying for a budget phone with compact design.

The music quality and stereo effects are good to hear in the headphone. The keypad is robust and comfortable to type.

Initially when the phone was introduced people complained about hanging problems and phone getting automatically restarted issues. Its been a week since I bought the phone and there are no issues till now.

Cons

The battery was a bit of a let down by Nokia. When I opened the back panel and found that the battery is the same old BL-5C that created a hullabaloo not long ago was psychologically disappointing.

The microUSB data cable that came along with the phone was incredibly short and there is absolutely no way I can place my phone on the table once I plugged it in the PC's USB slot.

Bluetooth is the only plausible data transfer option. The microUSB cable is short and there is no software CD in the package.

Inability to connect to Wi-Fi networks, lack of office tools, cheesy loud speakers at high volume, etc are desirable features missing on the phone.

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Virtual private network is a cost effective solution for companies to extend network connectivity to its employees in every corner of the globe. Consider a company sends an employee to another country that is far away from the company headquarters on a secret mission. There must be some way for the employee to retort to the company and access the private network of the company in a secure way. The company cannot install a private network across countries because it would be expensive. Therefore they must find a way to communicate with the employee in a secure manner using the internet. This is were a virtual private network comes in to the picture. A VPN is a private network connection that is virtual in the sense that there is no dedicated private physical network connecting the entities. But the traffic is sent via the public internet that is vulnerable to attack in a secure manner. Private traffic is carried on the public network in a safe manner using several technologies like encryption, firewalls, authentication, IPsec, etc. VPN gives an organization the freedom to clandestinely communicate with its outbound employees in an economical fashion.

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A housing complex in Kolkata is designed to tap solar energy and utilize it for household applications. It is also possible to feedback energy to the grid when excess power is available. The residents will also get paid for the power returned to the grid. This project is the first of its kind in the country and is expected to inspire the nation. This photo voltaic technology is already in use in Europe and other developed nations. Photo voltaic technology basically involves materials that emit electrons when light is incident on them. Our former president Abdul Kalam had also urged the young students of our country to research on photovoltaic energy. The solar tiles embedded on top of the roof in this complex are able to generate 2KW of power. When there is a shortage of solar power the grid will supply power and when solar power is surplus the reverse process happens. Tapping solar energy will bring down the internal temperature of houses during summer. Power will be available even when there is a conventional power cut. The most crucial aspect of solar powering homes is that it will reduce the amount of carbon emission which will have an impact on global warming. Cost is a major constraint in implementing the system in countries like India but things are looking up for the future.

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WaiverWire - the leading NFL resource on the web has launched a free tool known as "The Stimulus Package" to let NFL fans join the fantasy football bandwagon. The 2009 NFL season promises a visual treat to the fans and WaiverWire.com gives a bird's eye view of the NFL action on the web. Those who cannot afford the premium packages can access the tools and statistics offered by WaiverWire free of cost by signing up for "The Stimulus Package". My love for fantasy football is undying and my favorite NFL player is Knowshon Moreno. The high flying running back is a class apart and I love him for his on field acrobatic adventures. I'm expecting a brilliant show by my man this season and hopefully Denver can make it to the top this time. But my money is on Nnamdi Asomugha and he might turn out to be the extraordinary performer this season. Throughout this season I'll be keeping an eye on player statistics and rankings delivered by WaiverWire in the hunt for the best player of NFL 2009. People at my office often talk about their favorite players and flaunt their NFL knowledge. Now that I have signed up with WaiverWire, I can make use of the player comparison feature and give an apt repartee to them.

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Pasanga is an interesting film that touches the depths of childhood and school life. The film starts off in a wobbly manner with the kids being portrayed as naughty bugs and some of the scenes just fail to connect us to our own childhood. The director could have made a better attempt in depicting school life in my opinion. But the story settles down nicely interwoven with childhood egos and family sentiments. The love between Vimal and Vega is the most beautiful aspect of the movie. They are wacky yet passionate and capture our hearts with their sublime performance. The film has a strong message for parents. Parents must keep their own differences apart and encourage their children to succeed. The director has exhibited his true talent in the scene between the heads of both the families near a pond. The music is satisfactory with "Oru Vetkam Varuthe" and "Iraiva Iraiva" still lingering in my mind. Pasanga is a complete family entertainer and it is worth a watch.

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Yesterday I got a pen drive from my friend and inserted it into my PC. The pen drive had some video clips and pdf books which my friend had put from his system. Unfortunately when I opened the pen drive on my system, my anti-virus software alerted me about some viruses and worms in the pen drive. So I selected the heal option and some of the viruses where quarantined. After cleaning up I again opened the pen drive. To my surprise all the folders and files were missing and the drive was empty. I was very much disappointed because it had important data and I was eager to access them. When I checked the properties, it showed that the drive is full. So I got an idea. I just right clicked on the pen drive icon and clicked on search option. Voila! All the files became visible in the search results. I copied them from the search window in to my own hard drive. What a misery with viruses and worms..!

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