[Tutor] First Project - Ping Sweeper!

[Trent Rigsbee]

Hi! I've completed Learning to Program (off the website) and I've started to 
play around with code that I've found on Useless Python. I'm ready to start 
my first project! This may be way over my head, but I want to make a ping 
sweeper (put a range of IP addresses & ping to see which are vaild). I'm 
playing around with Mark Kels' Port Scanner off of Useless Python and I 
wanted to modify this for pinging but I'm stuck. I've ordered Network 
Programming for Python but I've started to play around with this until the 
book arrives. Any suggestions? Should I throw in the towel and make 
something simpler instead? Thanks! Here's the code that I'm tinkering with:

#A simple port scanner to scan a range of ports on a single host.

#Developers:
# 1.Mark Kels (mark.kels at gmail.com) - The basic port scanner
#Last updated:
# 21.5.2005

#----------Imports----------
from Tkinter import * #Used to make the GUI
import tkMessageBox #Used for error display
import socket #Used for connecting to ports
import threading #Used to make a difrent thread for the scan so it could be 
stopped

#--- Function to start a scan ---
def go():
    global app
    result.delete(1.0,END)
    app=scan()
    app.start() #start() is definde in threading.Thread
#--- Function to stop a scan ---
def stop():
    app.flag='stop'
#--- Function to clear the input and output ---
def clear():
    host_e.delete(0,END)
    start_port_e.delete(0,END)
    end_port_e.delete(0,END)
    result.delete(1.0,END)

#---The scan class which does the port scan itself---
class scan(threading.Thread):
    def _init_(self):
        threading.thread._init_(self)
    def run(self):
        self.host=host_e.get()
        self.start_port=int(start_port_e.get())
        self.end_port=int(end_port_e.get())
        self.open_counter=0
        self.flag='scan'
        start.config(text="Stop",command=stop)
        root.update()
        result.insert(END,"Scanning "+str(self.host)+"...\n\n")
        root.update()
        while self.start_port<=self.end_port and self.flag=='scan':
            self.sk=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.sk.settimeout(0.01) #closed ports take a long time to 
connect to, so if there is no connection after 0.01 seconds the port is 
closed
            try:
                self.sk.connect((self.host,self.start_port))
            except:
                pass #if connection fails (port is closed) pass and try with 
another port
            else:
                result.insert(END,str(self.start_port)+"\n")
                root.update()
                self.open_counter=self.open_counter+1
                self.sk.close()
            self.start_port=self.start_port+1
        if self.flag=='scan':
            result.insert(END,"\nDone !!\nFound "+str(self.open_counter)+" 
opened ports")
            root.update()
            start.config(text="Scan",command=go)
            root.update()
        elif self.flag=='stop':
            result.insert(END,"\n Scan stopped.")
            start.config(text="Scan",command=go)
            root.update()

#---The GUI---
root=Tk()
Label(root,text="Host: ").grid(row=1,column=1,sticky="w")
host_e=Entry(root)
host_e.grid(row=1,column=2,sticky="WE")
Label(root,text="Start port: ").grid(row=2,column=1,sticky="w")
start_port_e=Entry(root)
start_port_e.grid(row=2,column=2,sticky="WE")
Label(root,text="End port: ").grid(row=3,column=1,sticky="w")
end_port_e=Entry(root)
end_port_e.grid(row=3,column=2,sticky="WE")
start=Button(root,text="Scan",command=go)
start.grid(row=5,columnspan=3,sticky="WE")
clear=Button(root,text="Clear",command=clear)
clear.grid(row=6,columnspan=3,sticky="WE")
result=Text(root,width=20,height=20)
result.grid(row=7,columnspan=3,sticky="WENS")


root.wm_maxsize(width='190',height='370') #Set max size
root.wm_minsize(width='190',height='370') #Sat min size same as max size (so 
the window is unresizeable)
root.title("PPS 0.1") #Set the title of the window

root.mainloop()