基于Python socket的端口扫描程序

#-------------------------------------------------------------------------------
# Name:        PortScan
# Purpose:     扫描网段主机的端口开放情况
# Author:      Hao Chen
# Python3.4
#-------------------------------------------------------------------------------
import socket
def main():
    ip_start=input('请输入开始IP：(默认:127.0.0.1)')
    if ip_start=='':
        ip_start='127.0.0.1'
        ip_end='127.0.0.1'
    else:
        ip_end=input('请输入结束IP：')
        if ip_end=='':
            ip_end='127.0.0.1'
        
    s=input('请输入目标主机开始端口：(默认扫描常用端口)')
    if s=='':
        portList=[21, 22, 23, 25, 80, 135, 137, 139, 445, 1433, 1502, 3306, 3389, 8080, 9015]
    else:
        startport=int(s)
        s=input('请输入目标主机结束端口：(默认:65535)')
        if s=='':
            endport=65535
        else:
            endport=int(s)
        portList=[i for i in range(startport,endport+1)]
    
    while 1:
        #ip_startint(ip_end[x2+1:]):
            break;
        
        #开始扫描端口
        for port in portList:
            print('正在扫描%s ：%d' %(ip_start,port))
            try:
                sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                sk.settimeout(10)
                sk.connect((ip_start,port))
                sk.settimeout(None)
                print('Server %s port %d OK!' % (ip_start,port))
                sk.close()

                #结果保存在文件中
                f=open("IP_Port.txt",'a')
                f.write(ip_start+' : '+str(port)+'\n')
                f.close()               
            except Exception:
                print('Server %s port %d is not connected!' % (ip_start,port))
            
        #更新ip_start
        i=ip_start.rfind('.')
        x=int(ip_start[i+1:])+1
        ip_start=ip_start[:i+1]+str(x)
        
    print('扫描完成，结果保存在IP_Port.txt文件中')

if __name__ == '__main__':
    main()