Finding local IP addresses using Python's stdlib

Question

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?

Answer 1

netifaces is available via pip and easy_install. (I know, it's not in base, but it could be worth the install.)

netifaces does have some oddities across platforms:

• The localhost/loop-back interface may not always be included (Cygwin).
• Addresses are listed per-protocol (e.g., IPv4, IPv6) and protocols are listed per-interface. On some systems (Linux) each protocol-interface pair has its own associated interface (using the interface_name:n notation) while on other systems (Windows) a single interface will have a list of addresses for each protocol. In both cases there is a protocol list, but it may contain only a single element.

Here's some netifaces code to play with:

import netifaces

PROTO = netifaces.AF_INET   # We want only IPv4, for now at least

# Get list of network interfaces
# Note: Can't filter for 'lo' here because Windows lacks it.
ifaces = netifaces.interfaces()

# Get all addresses (of all kinds) for each interface
if_addrs = [netifaces.ifaddresses(iface) for iface in ifaces]

# Filter for the desired address type
if_inet_addrs = [addr[PROTO] for addr in if_addrs if PROTO in addr]

iface_addrs = [s['addr'] for a in if_inet_addrs for s in a if 'addr' in s]
# Can filter for '127.0.0.1' here.

The above code doesn't map an address back to its interface name (useful for generating ebtables/iptables rules on the fly). So here's a version that keeps the above information with the interface name in a tuple:

import netifaces

PROTO = netifaces.AF_INET   # We want only IPv4, for now at least

# Get list of network interfaces
ifaces = netifaces.interfaces()

# Get addresses for each interface
if_addrs = [(netifaces.ifaddresses(iface), iface) for iface in ifaces]

# Filter for only IPv4 addresses
if_inet_addrs = [(tup[0][PROTO], tup[1]) for tup in if_addrs if PROTO in tup[0]]

iface_addrs = [(s['addr'], tup[1]) for tup in if_inet_addrs for s in tup[0] if 'addr' in s]

And, no, I'm not in love with list comprehensions. It's just the way my brain works these days.

The following snippet will print it all out:

from __future__ import print_function  # For 2.x folks
from pprint import pprint as pp

print('\nifaces = ', end='')
pp(ifaces)

print('\nif_addrs = ', end='')
pp(if_addrs)

print('\nif_inet_addrs = ', end='')
pp(if_inet_addrs)

print('\niface_addrs = ', end='')
pp(iface_addrs)

Enjoy!