Finding local IP addresses using Python's stdlib

0 votes
asked Oct 3, 2008 by unkwntech

How can I find local IP addresses (i.e. 192.168.x.x or 10.0.x.x) in Python platform independently and using only the standard library?

30 Answers

0 votes
answered Jan 3, 2008 by jason-baker

I'm afraid there aren't any good platform independent ways to do this other than connecting to another computer and having it send you your IP address. For example: findmyipaddress. Note that this won't work if you need an IP address that's behind NAT unless the computer you're connecting to is behind NAT as well.

Here's one solution that works in Linux: get the IP address associated with a network interface.

0 votes
answered Oct 3, 2008 by vinko-vrsalovic
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.

0 votes
answered Oct 3, 2008 by dzinx

You can use the netifaces module. Just type:

easy_install netifaces

in your command shell and it will install itself on default Python installation.

Then you can use it like this:

from netifaces import interfaces, ifaddresses, AF_INET
for ifaceName in interfaces():
    addresses = [i['addr'] for i in ifaddresses(ifaceName).setdefault(AF_INET, [{'addr':'No IP addr'}] )]
    print '%s: %s' % (ifaceName, ', '.join(addresses))

On my computer it printed:

{45639BDC-1050-46E0-9BE9-075C30DE1FBC}: 192.168.0.100
{D43A468B-F3AE-4BF9-9391-4863A4500583}: 10.5.9.207

Author of this module claims it should work on Windows, UNIX and Mac OS X.

0 votes
answered Oct 3, 2008 by unkwntech

I just found this but it seems a bit hackish, however they say tried it on *nix and I did on windows and it worked.

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.connect(("8.8.8.8", 80))
print(s.getsockname()[0])
s.close()

This assumes you have an internet access, and that there is no local proxy.

0 votes
answered Oct 3, 2008 by dzinx

If you don't want to use external packages and don't want to rely on outside Internet servers, this might help. It's a code sample that I found on Google Code Search and modified to return required information:

def getIPAddresses():
    from ctypes import Structure, windll, sizeof
    from ctypes import POINTER, byref
    from ctypes import c_ulong, c_uint, c_ubyte, c_char
    MAX_ADAPTER_DESCRIPTION_LENGTH = 128
    MAX_ADAPTER_NAME_LENGTH = 256
    MAX_ADAPTER_ADDRESS_LENGTH = 8
    class IP_ADDR_STRING(Structure):
        pass
    LP_IP_ADDR_STRING = POINTER(IP_ADDR_STRING)
    IP_ADDR_STRING._fields_ = [
        ("next", LP_IP_ADDR_STRING),
        ("ipAddress", c_char * 16),
        ("ipMask", c_char * 16),
        ("context", c_ulong)]
    class IP_ADAPTER_INFO (Structure):
        pass
    LP_IP_ADAPTER_INFO = POINTER(IP_ADAPTER_INFO)
    IP_ADAPTER_INFO._fields_ = [
        ("next", LP_IP_ADAPTER_INFO),
        ("comboIndex", c_ulong),
        ("adapterName", c_char * (MAX_ADAPTER_NAME_LENGTH + 4)),
        ("description", c_char * (MAX_ADAPTER_DESCRIPTION_LENGTH + 4)),
        ("addressLength", c_uint),
        ("address", c_ubyte * MAX_ADAPTER_ADDRESS_LENGTH),
        ("index", c_ulong),
        ("type", c_uint),
        ("dhcpEnabled", c_uint),
        ("currentIpAddress", LP_IP_ADDR_STRING),
        ("ipAddressList", IP_ADDR_STRING),
        ("gatewayList", IP_ADDR_STRING),
        ("dhcpServer", IP_ADDR_STRING),
        ("haveWins", c_uint),
        ("primaryWinsServer", IP_ADDR_STRING),
        ("secondaryWinsServer", IP_ADDR_STRING),
        ("leaseObtained", c_ulong),
        ("leaseExpires", c_ulong)]
    GetAdaptersInfo = windll.iphlpapi.GetAdaptersInfo
    GetAdaptersInfo.restype = c_ulong
    GetAdaptersInfo.argtypes = [LP_IP_ADAPTER_INFO, POINTER(c_ulong)]
    adapterList = (IP_ADAPTER_INFO * 10)()
    buflen = c_ulong(sizeof(adapterList))
    rc = GetAdaptersInfo(byref(adapterList[0]), byref(buflen))
    if rc == 0:
        for a in adapterList:
            adNode = a.ipAddressList
            while True:
                ipAddr = adNode.ipAddress
                if ipAddr:
                    yield ipAddr
                adNode = adNode.next
                if not adNode:
                    break

Usage:

>>> for addr in getIPAddresses():
>>>    print addr
192.168.0.100
10.5.9.207

As it relies on windll, this will work only on Windows.

0 votes
answered Jan 30, 2009 by gavaletz

FYI I can verify that the method:

import socket
addr = socket.gethostbyname(socket.gethostname())

Works in OS X (10.6,10.5), Windows XP, and on a well administered RHEL department server. It did not work on a very minimal CentOS VM that I just do some kernel hacking on. So for that instance you can just check for a 127.0.0.1 address and in that case do the following:

if addr == "127.0.0.1":
     import commands
     output = commands.getoutput("/sbin/ifconfig")
     addr = parseaddress(output)

And then parse the ip address from the output. It should be noted that ifconfig is not in a normal user's PATH by default and that is why I give the full path in the command. I hope this helps.

0 votes
answered Oct 12, 2009 by alexander
import socket
print([ip for ip in socket.gethostbyname_ex(socket.gethostname())[2] if not ip.startswith("127.")][:1])

I'm using this, because one of the computers I was on had an /etc/hosts with duplicate entries and references to itself. socket.gethostbyname() only returns the last entry in /etc/hosts. This solution weeds out the ones starting with "127.". Works with Python 3 and 2.5, possibly other versions too. Does not deal with several network devices or IPv6. Works on Linux and Windows.

Update: The above technique stopped working on recent Linux distros. This can be used instead:

import socket
print([(s.connect(('8.8.8.8', 53)), s.getsockname()[0], s.close()) for s in [socket.socket(socket.AF_INET, socket.SOCK_DGRAM)]][0][1])

Update: Created a long one-liner that combines the two one-liners above. Should work everywhere (Linux, Windows, OS X, Python 2.x and Python 3):

import socket
print([l for l in ([ip for ip in socket.gethostbyname_ex(socket.gethostname())[2] if not ip.startswith("127.")][:1], [[(s.connect(('8.8.8.8', 53)), s.getsockname()[0], s.close()) for s in [socket.socket(socket.AF_INET, socket.SOCK_DGRAM)]][0][1]]) if l][0][0])

Note that this may throw an exception if no IP is configured.

Finally, as an alias called myip:

alias myip="python -c 'import socket; print([l for l in ([ip for ip in socket.gethostbyname_ex(socket.gethostname())[2] if not ip.startswith(\"127.\")][:1], [[(s.connect((\"8.8.8.8\", 53)), s.getsockname()[0], s.close()) for s in [socket.socket(socket.AF_INET, socket.SOCK_DGRAM)]][0][1]]) if l][0][0])'"
0 votes
answered Oct 22, 2009 by smerlin

im using following module:

#!/usr/bin/python
# module for getting the lan ip address of the computer

import os
import socket

if os.name != "nt":
    import fcntl
    import struct
    def get_interface_ip(ifname):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        return socket.inet_ntoa(fcntl.ioctl(
                s.fileno(),
                0x8915,  # SIOCGIFADDR
                struct.pack('256s', bytes(ifname[:15], 'utf-8'))
                # Python 2.7: remove the second argument for the bytes call
            )[20:24])

def get_lan_ip():
    ip = socket.gethostbyname(socket.gethostname())
    if ip.startswith("127.") and os.name != "nt":
        interfaces = ["eth0","eth1","eth2","wlan0","wlan1","wifi0","ath0","ath1","ppp0"]
        for ifname in interfaces:
            try:
                ip = get_interface_ip(ifname)
                break;
            except IOError:
                pass
    return ip

Tested with windows and linux (and doesnt require additional modules for those) intended for use on systems which are in a single IPv4 based LAN.

The fixed list of interface names does not work for recent linux versions, which have adopted the systemd v197 change regarding predictable interface names as pointed out by Alexander. In such cases, you need to manually replace the list with the interface names on your system, or use another solution like netifaces.

0 votes
answered Oct 5, 2010 by shino

I use this on my ubuntu machines:

import commands
commands.getoutput("/sbin/ifconfig").split("\n")[1].split()[1][5:]
0 votes
answered Jan 13, 2011 by viker

One simple way to produce "clean" output via command line utils:

import commands
ips = commands.getoutput("/sbin/ifconfig | grep -i \"inet\" | grep -iv \"inet6\" | " +
                         "awk {'print $2'} | sed -ne 's/addr\:/ /p'")
print ips

It will show all IPv4 addresses on the system.

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