Wednesday, December 17, 2008

Command Line Argument Processor Library for Java Applications

Just came across a library which can be used to ease the task of command line argument processing. I should say it is truly based on an elaborate study as it covers almost all the possible paradigms of command line arguments. It is capable of validating all arguments passed. You can also form sets of arguments which need to be passed as a group. Moreover your program looks more professional as the parameters you accept can adhere to common standards used to pass arguments to programs on Linux/Windows Operating systems. I will try to post some examples of how easy it is to use this helper class J

Thank you, Dr. Matthias for such a wonderful piece of code.

For more information see Processing command line arguments in Java: Case closed.

Monday, July 14, 2008

Privacy Policy and Terms & Conditions for Free: The Developers Pain Eased

Privacy Policy and Terms and Conditions can be a headache for freelancer. TelePro released a sample of Privacy Policy, Copyright Notice and Terms and Conditions for everyone to download without any charge or obligation. You can feel free to use them on your own projects. A link back to Free Website Legal Documents would be appreciated but is not required.

There is another online customized Privacy Policy Generator by Direct Marketing Association.

List of Common Password Reset/Challenge Questions

Have you ever forgotten your password? Well I have J. Truly speaking now-a-days internet users have too many accounts & passwords to remember and so forgetting them is fairly common. In fact it is the most common help desk request. To ease these support guys many web-sites are opting for using automated password recovery mechanism wherein the user who forgot the password is challenged with a question which he/she had selected while creating the account. If the user answers the question correctly, the password is reset or sent to the users email account.

As this feature saves a lot of money for the website owners, and also saves the users a lot of time & efforts involved in recovering the password, it has now become a STANDARD. Consequently web developers have to face the challenge of populating the security question drop-down with the most common challenge questions which not only suit everyone one but are also easy to understand and remember.

I also faced such a problem recently but couldn't find a set of such questions published anywhere even after intensive "googling" :P Well don't doubt my searching skills J

So I decided to post one here itself, for the reference of all those enthu developers/designers round the world

Here it goes:

  • What is the first and last name of your first boyfriend or girlfriend?
  • Which phone number do you remember most from your childhood?
  • What was your favorite place to visit as a child?
  • Who is your favorite actor, musician, or artist?
  • What is the name of your favorite pet?
  • In what city were you born?
  • What high school did you attend?
  • What is the name of your first school?
  • What is your favorite movie?
  • What is your mother's maiden name?
  • What street did you grow up on?
  • What was the make of your first car?
  • When is your anniversary?
  • What is your favorite color?
  • What is your father's middle name?
  • What is the name of your first grade teacher?
  • What was your high school mascot?
  • Which is your favorite web browser?

I will surely add to these if I am able to figure out any more… If you know any feel; free to add them in the comments area.

Saturday, July 12, 2008

Setting up FTP Server on Ubuntu – Amazon EC2

File Transfer Protocol (FTP) is a TCP protocol for uploading and downloading files between computers. FTP works on a client/server model. The server component is called an FTP daemon. It continuously listens for FTP requests from remote clients. When a request is received, it manages the the login and sets up the connection. For the duration of the session it executes any of commands sent by the FTP client.

Access to an FTP server can be managed in two ways:

  • Anonymous
  • Authenticated

In the Anonymous mode, remote clients can access the FTP server by using the default user account called 'anonymous" or "ftp" and sending an email address as the password. In the Authenticated mode a user must have an account and a password. User access to the FTP server directories and files is dependent on the permissions defined for the account used at login. As a general rule, the FTP daemon will hide the root directory of the FTP server and change it to the FTP Home directory. This hides the rest of the file system from remote sessions.

Amazon EC2: Unblock FTP port

FTP works on port 21 by default. This port is blocked by the AWS firewall. You must unblock this port (21) by changing the instance permissions prior to setting up FTP so that you can access FTP remotely. This can be done using the AWS EC2 Elastic Fox client. Please refer to my other post about Unblocking ports on the Amazon EC2 for more details.

vsftpd - FTP Server Installation

vsftpd is an FTP daemon available in Ubuntu. It is easy to install, set up, and maintain. To install vsftpd you can run the following command:


sudo apt-get install vsftpd

vsftpd - FTP Server Configuration

You can edit the vsftpd configuration file, /etc/vsftpd.conf, to change the default settings. By default only anonymous FTP is allowed. If you wish to disable this option, you should change the following line:

anonymous_enable=YES

to

anonymous_enable=NO

By default, local system users are not allowed to login to FTP server. To change this setting, you should uncomment the following line:

#local_enable=YES

By default, users are allowed to download files from FTP server. They are not allowed to upload files to FTP server. To change this setting, you should uncomment the following line:

#write_enable=YES

Similarly, by default, the anonymous users are not allowed to upload files to FTP server. To change this setting, you should uncomment the following line:

#anon_upload_enable=YES

The configuration file consists of many configuration parameters. The information about each parameter is available in the configuration file. Alternatively, you can refer to the man page, man 5 vsftpd.conf for details of each parameter.

Once you configure vsftpd you can start the daemon. You can run following command to run the vsftpd daemon:


sudo /etc/init.d/vsftpd start

 

Please note that the defaults in the configuration file are set as they are for security reasons. Each of the above changes makes the system a little less secure, so make them only if you need them.