python 探測端口

最近在学习网络安全课程，探测对方哪个端口开启是黑客攻击的第一步：
写了一段探测对方端口的代码
使用格式：python -H 目标IP地址 -P 目标端口列表
 1 # coding=UTF-8
 2 import socket
 3 import optparse
 4 import threading
 5 screenLock = threading.Semaphore(value=1)
 6 def connScan(tgtHost,tgtPort):
 7     try:
 8         connSkt = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
 9         connSkt.connect((tgtHost,tgtPort))
10         connSkt.send('ViolentPython
')
11         results = connSkt.recv(100)
12         screenLock.acquire()
13         print('[+]%d/tcp open'%tgtPort)
14         print ('[+] '+str(results))
15         
16     except:
17         screenLock.acquire()#加锁
18         print ('[-]%d/tcp closed'%tgtPort)
19     finally:
20         screenLock.release()
21         connSkt.close()
22         
23         
24 def portScan(tgtHost,tgtPorts):
25     try:
26         tgtIP =socket.gethostbyname(tgtHost)
27         
28     except:
29         print "[-]Cannot resolve '%s':Unknown host" % tgtHost
30         return
31     try:
32         tgtName = socket.gethostbyaddr(tgtIP)
33         print "
[+] Scan Results for :"+ tgtName[0]
34     except:
35         print "
[+] Scan Results for:" + tgtIP
36     socket.setdefaulttimeout(1)
37     
38     for tgtPort in tgtPorts:
39         print "Scanning port"+ str(tgtPort)
40         t = threading.Thread(target=connScan,args=(tgtHost,int(tgtPort)))
41         t.start()
42         
43 def main():
44     parser = optparse.OptionParser('usage%prog -H<target host> -p <target port>')
45     parser.add_option('-H',dest='tgtHost',type='string',help='specify target host')
46     parser.add_option('-p',dest='tgtPort',type='int',help='specify target port')
47     (options,args)=parser.parse_args()
48     tgtHost = options.tgtHost
49     tgtPort = options.tgtPort
50     args.append(tgtPort)
51     if(tgtHost == None)|(tgtPort == None):
52         return('[-] You must specify a target host and port[s]!')
53         exit(0)
54     portScan(tgtHost,args)
55     
56     
57 if __name__ == '__main__':
58     main()
59     
下一步，准备写成一个可用的界面应用程序。