Python, How to get all external ip addresses with multiple NICs

StackOverflow https://stackoverflow.com/questions/8281371

  •  09-03-2021
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Question

What is the most efficient way to get all of the external ip address of a machine with multiple nics, using python? I understand that an external server is neeeded (I have one available) but am un able to find a way to find a good way to specify the nic to use for the connection (So I can use a for loop to iterate through the various nics). Any advice about the best way to go about this?

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Solution

You should use netifaces. It is designed to be cross-platform on Mac OS X, Linux, and Windows.

>>> import netifaces as ni
>>> ni.interfaces()
['lo', 'eth0', 'eth1', 'vboxnet0', 'dummy1']
>>> ni.ifaddresses('eth0')
{17: [{'broadcast': 'ff:ff:ff:ff:ff:ff', 'addr': '00:02:55:7b:b2:f6'}], 2: [{'broadcast': '24.19.161.7', 'netmask': '255.255.255.248', 'addr': '24.19.161.6'}], 10: [{'netmask': 'ffff:ffff:ffff:ffff::', 'addr': 'fe80::202:55ff:fe7b:b2f6%eth0'}]}
>>> 
>>> ni.ifaddresses.__doc__
'Obtain information about the specified network interface.\n\nReturns a dict whose keys are equal to the address family constants,\ne.g. netifaces.AF_INET, and whose values are a list of addresses in\nthat family that are attached to the network interface.'
>>> # for the IPv4 address of eth0
>>> ni.ifaddresses('eth0')[2][0]['addr']
'24.19.161.6'

The numbers used to index protocols are from /usr/include/linux/socket.h (in Linux)...

#define AF_INET         2       /* Internet IP Protocol         */
#define AF_INET6        10      /* IP version 6                 */
#define AF_PACKET       17      /* Packet family                */

OTHER TIPS

For the general case, there is no solution. Consider the case where the local machine is behind a machine with two IP addresses doing NAT. You can change your local interface to anything you like, but it's unlikely that you'll convince the NAT machine to make a different routing decision on its outgoing connections.

Required: WMI / PyWin32 (https://sourceforge.net/projects/pywin32/)

Use the following snippet to get the IP of the network card(s) on Windows.

import wmi
c = wmi.WMI()

for interface in c.Win32_NetworkAdapterConfiguration(IPEnabled=1):
    print("Description: " + interface.Description)
    print("IP: " + str(interface.IPAddress[0]))
    print("MAC: " + str(interface.IPAddress[1]))

For more information on what parameters you can provide Win32_NetworkAdapterConfiguration with visit: https://msdn.microsoft.com/en-us/library/aa394217(v=vs.85).aspx

Get address of all NICs without any external package

import socket
print socket.gethostbyname_ex(socket.gethostname())[2]

Use the subprocess module to connect to your usual systems tools like ifconfig or netstat:

>>> import subprocess
>>> print subprocess.check_output(['ifconfig'])
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