一个用python写的简单的端口扫描器，python环境为 3.7.0，windows系统

扫描给定主机是否开放了指定的端口
TCP连接扫描是利用TCP的三次握手来确定主机的端口是否开放。确定主机端口开放之后，给端口发送消息，接收端口返回的消息，然后判断该端口运行的服务。
使用时，-H 参数可以提供主机的域名或者ip地址，-p/-P 写要扫描的端口，多个端口用逗号分隔

'''
@Author:yw
参考书籍:《python绝技：运用python成为顶级***》
'''
import optparse
from socket import *
import threading
threadlock = threading.Lock() #实例化threadlock对象

def Conn_scan(Host, Port):
    try:
        conn = socket(AF_INET,SOCK_STREAM)
        conn.connect((Host, Port))
        #conn.send('ywboy'.encode('utf-8')) #发送测试
        #results = conn.recv(100)           #接收主机返回的信息
        threadlock.acquire()                 #加锁
        print("[+]%d/tcp Open" % Port)
        #print('[+]'+results.decode('utf-8'))
        conn.close()
    except Exception as e:
        threadlock.acquire()                 #释放锁
        print('[-]%d/Tcp Closed' % Port)
    finally:
        threadlock.release()
        conn.close()
def Port_scan(Host, Ports):
    try:
        IP = gethostbyname(Host)        ##获得对应主机的ip地址
    except:
        print("[-] Cannot resolve '%s':Unknow host" % Host)
        return
    try:
        Name = gethostbyaddr(Host)          ##获得对应主机的信息,返回主机名、主机别名列表、主机IP地址列表
        print("\n[+] Scan result for:"+Name[0])
    except:
        print("\n[+] Scan Results for:"+IP)
    setdefaulttimeout(1)
    for Port in Ports:
        print("Scan port:"+Port)
        Conn_scan(Host, int(Port))
def main():
    usage = "usage %prog -H  -p/-P "
    parse = optparse.OptionParser(usage)
    parse.add_option('-H', dest='Host', type='string', help='target Host')
    parse.add_option('-p','-P', dest='Ports', type='string', help='SCan Port')
    (options, args) = parse.parse_args()
    Host = options.Host
    Ports = str(options.Ports).split(',')
    if (Host==None)|(Ports==None):
        print(parse.usage)
        exit(0)
    Port_scan(Host,Ports)
if __name__ == '__main__':
    main()

上述代码，因为我只是做了端口扫描，所以注释掉的判断端口扫描服务的代码

运行结果：