python - 如何在 Python 中解析 DNS？

Question

我有一个 DNS 脚本，它允许用户通过在 Windows 命令提示符下键入网站名称来解析 DNS 名称。

我浏览了几个关于 DNS 解析的指南，但我的脚本似乎仍然无法将名称 (www.google.com) 或 (google.com) 解析为 IP 地址。

脚本输出错误

Traceback (most recent call last):
  File "C:\python\main_menu.py", line 37, in ?
    execfile('C:\python\showdns.py')
  File "C:\python\showdns.py", line 3, in ?
    x = input ("\nPlease enter a domain name that you wish to translate: ")
  File "<string>", line 0, in ?
NameError: name 'google' is not defined

编码：

import socket

x = input ("\nPlease enter a domain name that you wish to translate: ")

print ("\n\nThe IP Address of the Domain Name is: "+socket.gethostbyname_ex(x))

x = raw_input("\nSelect enter to proceed back to Main Menu\n")
if x == '1': 
execfile('C:\python\main_menu.py')

请提供有关代码的建议。谢谢！

Answer 1

input() 是在这里使用的错误函数。它实际上评估用户输入的字符串。

此外gethostbyname_ex返回的不仅仅是一个字符串。所以你的打印语句也会失败。

在您的情况下，此代码应该可以工作：

import socket

x = raw_input ("\nPlease enter a domain name that you wish to translate: ")  

data = socket.gethostbyname_ex(x)
print ("\n\nThe IP Address of the Domain Name is: "+repr(data))  

x = raw_input("\nSelect enter to proceed back to Main Menu\n")  
if x == '1':   
    execfile('C:\python\main_menu.py')  

Answer 2

#!/user/bin/env python
"""
Resolve the DNS/IP address of a given domain
data returned is in the format:
(name, aliaslist, addresslist)
@filename resolveDNS.py
@version 1.01 (python ver 2.7.3)
@author LoanWolffe
"""
import socket

def getIP(d):
    """
    This method returns the first IP address string
    that responds as the given domain name
    """
    try:
        data = socket.gethostbyname(d)
        ip = repr(data)
        return ip
    except Exception:
        # fail gracefully!
        return False
#
def getIPx(d):
    """
    This method returns an array containing
    one or more IP address strings that respond
    as the given domain name
    """
    try:
        data = socket.gethostbyname_ex(d)
        ipx = repr(data[2])
        return ipx
    except Exception:
        # fail gracefully!
        return False
#
def getHost(ip):
    """
    This method returns the 'True Host' name for a
    given IP address
    """
    try:
        data = socket.gethostbyaddr(ip)
        host = repr(data[0])
        return host
    except Exception:
        # fail gracefully
        return False
#
def getAlias(d):
    """
    This method returns an array containing
    a list of aliases for the given domain
    """
    try:
        data = socket.gethostbyname_ex(d)
        alias = repr(data[1])
        #print repr(data)
        return alias
    except Exception:
        # fail gracefully
        return False
#

# test it

x = raw_input("Domain name or IP address? > ")


a = getIP(x)
b = getIPx(x)
c = getHost(x)
d = getAlias(x)

print " IP ", a
print " IPx ", b
print " Host ", c
print " Alias ", d

Answer 3

使用raw_input而不是input.