Finding the IP address of a particular network interface may be needed from your Python network application.
This recipe is prepared exclusively for a Linux box. There are some Python modules specially designed to bring similar functionalities on Windows and Mac platforms. For example, see http://sourceforge.net/projects/pywin32/ for Windows-specific implementation.
You can use the fnctl module to query the IP address on your machine.
Listing 3.5 shows us how to find the IP address for a specific interface on your machine, as follows:
#!/usr/bin/env python
# Python Network Programming Cookbook -- Chapter – 3
# This program is optimized for Python 2.7.
# It may run on any other version with/without modifications.
import argparse
import sys
import socket
import fcntl
import struct
import array
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])
if __name__ == '__main__':
#interfaces = list_interfaces()
parser = argparse.ArgumentParser(description='Python networking utils')
parser.add_argument('--ifname', action="store", dest="ifname", required=True)
given_args = parser.parse_args()
ifname = given_args.ifname
print "Interface [%s] --> IP: %s" %(ifname, get_ip_address(ifname)) The output of this script is shown in one line, as follows:
$ python 3_5_get_interface_ip_address.py --ifname=eth0 Interface [eth0] --> IP: 10.0.2.15
This recipe is similar to the previous one. The preceding script takes a command-line argument: the name of the network interface whose IP address is to be known. The
get_ip_address() function creates a socket object and calls the fnctl.ioctl() function to query on that object about IP information. Note that the socket.inet_ntoa() function converts the binary data to a human-readable string in a dotted format as we are familiar with it.