Programming assignment P1

• Simplified Mail User Agent
  • The standard Dickinson mail server (exmail.dickinson.edu) does not permit unauthenticated sending of messages. For this lab, you should use Dickinson's legacy mail server, which is mail.dickinson.edu.
  • Estimated completion time: one hour
• UDP Pinger
  • Although the assignment does not explicitly say so, your client program should print out the contents and round-trip time for each packet that yields a response, and a suitable error message for packets that do not yield a response. So your output should look something like this:

         Received from 127.0.0.1: PING 0 Fri Jan 16 12:26:53 EST 2009
         Round-trip time was 168 milliseconds
         
         Received from 127.0.0.1: PING 1 Fri Jan 16 12:26:54 EST 2009
         Round-trip time was 17 milliseconds
         
         receive timed out -- packet assumed lost
         
         Received from 127.0.0.1: PING 3 Fri Jan 16 12:26:59 EST 2009
         Round-trip time was 58 milliseconds
         
         Received from 127.0.0.1: PING 4 Fri Jan 16 12:27:00 EST 2009
         Round-trip time was 88 milliseconds
         
         Received from 127.0.0.1: PING 5 Fri Jan 16 12:27:01 EST 2009
         Round-trip time was 132 milliseconds
         
         receive timed out -- packet assumed lost
         
         Received from 127.0.0.1: PING 7 Fri Jan 16 12:27:06 EST 2009
         Round-trip time was 87 milliseconds
         
         ...

  • A useful snippet for producing a string with the current date and time is:

    	      Date now = new Date(System.currentTimeMillis());
    	      String nowString = now.toString();

  • As stated in the assignment, you will need to investigate the API of DatagramSocket in order to implement the receive timeout. Hint: you will need to surround the receive call with an appropriate try/catch block.
  • Estimated completion time: two hours