为什么我的程序没有输出

Question

我用socket创建一个tcp连接，并检查服务器端口443是否打开。

#!/usr/bin/env python 
import socket 
import subprocess 
import sys 
from datetime import datetime 

subprocess.call('clear', shell=True) 

remoteServer = raw_input("Enter a remote host to scan: ") 
remoteServerIP = socket.gethostbyname(remoteServer) 

print "-" * 60 
print "Please wait, scanning remote host", remoteServerIP 
print "-" * 60 

t1 = datetime.now() 

try: 
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
    result = sock.connect_ex((remoteServerIP, 443)) 
    if result == 0: 
     print "Port {443}: Open" 
    else: 
     print "Port {443}: Close" 
    sock.close() 

except KeyboardInterrupt: 
    print "You pressed Ctrl+C" 
    sys.exit() 

except socket.gaierror: 
    print 'Hostname could not be resolved. Exiting' 
    sys.exit() 

except socket.error: 
    print "Couldn't connect to server" 
    sys.exit() 

t2 = datetime.now() 
total = t2 - t1 
print 'Scanning Completed in: ', total 

有时候，我得到了输出，open或close，但有时我没有输出。例如，我输入64.233.160.2或64.233.160.3，否输出open或close输出。我怎么了？

Answer 1

最可能的原因是您尝试连接的计算机既不接受也不主动拒绝连接。尝试设置连接超时（https://docs.python.org/2/library/socket.html#socket.socket.settimeout）。

您的程序在您按Ctrl-C时才会退出，这表明socket.connect呼叫处于阻止状态。