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

# coding=UTF-8
import socket
import optparse
import threading
screenLock = threading.Semaphore(value=1)
def connScan(tgtHost,tgtPort):
    try:
        connSkt = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        connSkt.connect((tgtHost,tgtPort))
        connSkt.send('ViolentPython
')
        results = connSkt.recv(100)
        screenLock.acquire()
        print('[+]%d/tcp open'%tgtPort)
        print ('[+] '+str(results))
        
    except:
        screenLock.acquire()#加锁
        print ('[-]%d/tcp closed'%tgtPort)
    finally:
        screenLock.release()
        connSkt.close()
        
        
def portScan(tgtHost,tgtPorts):
    try:
        tgtIP =socket.gethostbyname(tgtHost)
        
    except:
        print "[-]Cannot resolve '%s':Unknown host" % tgtHost
        return
    try:
        tgtName = socket.gethostbyaddr(tgtIP)
        print "
[+] Scan Results for :"+ tgtName[0]
    except:
        print "
[+] Scan Results for:" + tgtIP
    socket.setdefaulttimeout(1)
    
    for tgtPort in tgtPorts:
        print "Scanning port"+ str(tgtPort)
        t = threading.Thread(target=connScan,args=(tgtHost,int(tgtPort)))
        t.start()
        
def main():
    parser = optparse.OptionParser('usage%prog -H<target host> -p <target port>')
    parser.add_option('-H',dest='tgtHost',type='string',help='specify target host')
    parser.add_option('-p',dest='tgtPort',type='int',help='specify target port')
    (options,args)=parser.parse_args()
    tgtHost = options.tgtHost
    tgtPort = options.tgtPort
    args.append(tgtPort)
    if(tgtHost == None)|(tgtPort == None):
        return('[-] You must specify a target host and port[s]!')
        exit(0)
    portScan(tgtHost,args)
    
    
if __name__ == '__main__':
    main()
    
下一步，准备写成一个可用的界面应用程序。