Recitation 8 (R8)

CT 320: Network and Systems Administration

Group Work, COMSC 315 Lab

Python Port Scanner

The purpose of this assignment is to learn about network security by writing a Python port scanner that detects which network ports are open on a system, and by using the same program to gather statistics on multiple systems.

Description

For this assignment you will turn in a program called Scanner.py that checks network ports to see if a server has the port open for use by a service. The program has the following command line options:

    ./Scanner.py -a <host> -p <port> -f <filename> -h <page> 

The <host> parameter is an IP address or host name, the <port> parameter is a number between 0 and 65535 or ‘all’, the <filename> parameter is a text file with host names, and the <page> parameter is the page to be fetched via HTTP.

Part 1 — Scanning a single port

Implement scanning of a single port using the following command:

    ./Scanner.py -a <host> -p <port> 

Use a function to scan the specified address and port, as follows:

    def scan_server(address, port): 

The function should create a socket and connect to the host on the specified port. If the connection is accepted the function should return true, else it should return false. The function should also print “Connected to server <host> on port <port>.” to standard error. Do not print anything if no connection is established. Test the program on the www.cs.colostate.edu server, port 80.

Part 2 — Scanning all ports

Implement scanning of all ports using the following command:

    ./Scanner.py -a <host> -p all 

Make the program loop through all ports between 0 and 1023 on the specified system. You should set the socket timeout to a small number such as 0.05s. Test on www.cs.colostate.edu (server), waters.cs.colostate.edu (workstation), and localhost to see which ports are open. Explain which ports are open on these three systems and which protocols they support. Try disabling a service on localhost and see how the list of open ports changes.

Part 3 — Gather Statistics

Change Scanner.py to optionally read:

    ./Scanner.py -f <file> -p <port> 

The program should scan all the ports on each system in the file, and return statistics on the number of open ports across all systems. Test the program using an input file with the following:

    www.cs.colostate.edu 
    www.math.colostate.edu 
    www.physics.colostate.edu 
    www.languages.colostate.edu 
    www.maps.colostate.edu 
    www.csurams.com 
    www.admissions.colostate.edu 
    www.ramct.colostate.edu 

The program should print accumulated statistics for all of the ports between 0 and 1023 for all of the above servers. Do not print ports that have no open connections on any of the systems. Here is the sample output:

    <number> systems had port <port> open. 

Part 4 — HTTP requests

Add a command to Scanner.py that connects to the specified host and port and sends an HTTP request for the specified <page>. Write the code that receives the return HTTP message and parses it, displaying only the HTM data returned. Test the command on www.cs.colostate.edu/~ct320. The command syntax should be extended to specify the server page desired using the ‘h’ option, as shown below.

    ./Scanner.py -a <host> -p <port> -h <page>

Checkin

Submit your Scanner.py file into the drop box on RamCT for Recitation 8 (R8).