How to Get the Ip Address from a Nic (Network Interface Controller) in Python

How can I get the IP address from a NIC (network interface controller) in Python?

Two methods:

Method #1 (use external package)

You need to ask for the IP address that is bound to your eth0 interface. This is available from the netifaces package

import netifaces as ni
ip = ni.ifaddresses('eth0')[ni.AF_INET][0]['addr']
print(ip)  # should print "192.168.100.37"

You can also get a list of all available interfaces via

ni.interfaces()

Method #2 (no external package)

Here's a way to get the IP address without using a python package:

import socket
import fcntl
import struct

def get_ip_address(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(fcntl.ioctl(
        s.fileno(),
        0x8915,  # SIOCGIFADDR
        struct.pack('256s', ifname[:15])
    )[20:24])

get_ip_address('eth0')  # '192.168.0.110'

Note: detecting the IP address to determine what environment you are using is quite a hack. Almost all frameworks provide a very simple way to set/modify an environment variable to indicate the current environment. Try and take a look at your documentation for this. It should be as simple as doing

if app.config['ENV'] == 'production':
  # send production email
else:
  # send development email

How to get Network Interface Card names in Python?

I don't think there's anything in the standard library to query these names.

If I needed these names on a Linux system I would parse the output of ifconfig or the contents of /proc/net/dev. Look at this blog entry for a similar problem.

How to get the physical interface IP address from an interface

You should use netifaces. It is designed to be cross-platform and contains specialised code for Windows together with a variety of generic versions that work on different UNIX/UNIX-like platforms.

As of netifaces version 0.10.0, Python3 is supported.

Usage Summary

>>> from netifaces import AF_INET, AF_INET6, AF_LINK, AF_PACKET, AF_BRIDGE
>>> import netifaces as ni
>>> ni.interfaces()
['lo', 'eth0', 'eth1', 'vboxnet0', 'dummy1']
>>>
>>> ni.ifaddresses('eth0')[AF_LINK]   # NOTE: AF_LINK is an alias for AF_PACKET
[{'broadcast': 'ff:ff:ff:ff:ff:ff', 'addr': '00:02:55:7b:b2:f6'}]
>>> ni.ifaddresses('eth0')[AF_INET]
[{'broadcast': '172.16.161.7', 'netmask': '255.255.255.248', 'addr': '172.16.161.6'}]
>>>
>>> # eth0 ipv4 interface address
>>> ni.ifaddresses('eth0')[AF_INET][0]['addr']
'172.16.161.6'
>>>>

Details

Windows Support:

No compiler required for most MS Windows installs. If you get warnings about installing MS Visual C++ for Windows, be very careful because you need to match the version of compiler used for your python with that used for the module.

Detailed example of netifaces data structures:

>>> 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': '172.16.161.7',
            'netmask': '255.255.255.248',
            'addr': '172.16.161.6'
        }
    ],
    10: [
        {
            'netmask': 'ffff:ffff:ffff:ffff::',
            'addr': 'fe80::202:55ff:fe7b:b2f6%eth0'
        }
    ]
}
>>> 
>>> print(ni.ifaddresses.__doc__)
Obtain information about the specified network interface.

Returns a dict whose keys are equal to the address family constants,
e.g. netifaces.AF_INET, and whose values are a list of addresses in
that family that are attached to the network interface.
>>>
>>> # for the IPv4 address of eth0
>>> ni.ifaddresses('eth0')[2][0]['addr']
'172.16.161.6'

The numbers used to index protocols are from /usr/include/linux/socket.h (in Linux)... EDIT: my 3.2 kernel has them here: /usr/src/linux-headers-3.2.0-4-common/include/linux/socket.h

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

The good news is that you don't have to remember all those header constants, they are included with netifaces:

>>> from netifaces import AF_INET, AF_INET6, AF_LINK, AF_PACKET, AF_BRIDGE
>>> import netifaces as ni

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

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                */

Finding local IP addresses using Python's stdlib

import socket
socket.gethostbyname(socket.gethostname())

This won't work always (returns 127.0.0.1 on machines having the hostname in /etc/hosts as 127.0.0.1), a paliative would be what gimel shows, use socket.getfqdn() instead. Of course your machine needs a resolvable hostname.

bind/connect to network interface card using python

Actually the answer is very simple. And its similar to what Idx did in the previous answer:

def findConnectedRobot():

'''
Finds which robots are connected to the computer and returns the
addresses of the NIC they are connected to
'''
robot_address = []  # stores NIC address
import netifaces
# get the list of availble NIC's
for card in netifaces.interfaces():
    try:
        # get all NIC addresses
        temp = netifaces.ifaddresses(\
                card)[netifaces.AF_INET][0]['addr']
        temp2 = temp.split('.')
        # see if address matches common address given to NIC when
        # NIC is connected to a robot
        if temp2[0] == '192' and int(temp2[3]) < 30:
            print('appending address: ' + temp)
            robot_address.append(temp)
    except BaseException:
        pass
return robot_address

After I get the "robot addresses" then I can just bind/connected to them like a normal socket.

Thanks for the help!

How do I get my local ip address from a python script on linux?

You can use an external package, for example netifaces, or you can look for the ipaddress of a given interface, specified by its name. Take a look at this question.

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